diff --git a/src/bignum.h b/src/bignum.h
index f5d545f07e..135eade679 100644
--- a/src/bignum.h
+++ b/src/bignum.h
@@ -115,9 +115,9 @@ public:
     {
         unsigned long n = BN_get_word(this);
         if (!BN_is_negative(this))
-            return (n > INT_MAX ? INT_MAX : n);
+            return (n > std::numeric_limits<int>::max() ? std::numeric_limits<int>::max() : n);
         else
-            return (n > INT_MAX ? INT_MIN : -(int)n);
+            return (n > std::numeric_limits<int>::max() ? std::numeric_limits<int>::min() : -(int)n);
     }
 
     void setint64(int64 n)
diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index cd08d95d29..fdb1b34a0a 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -950,7 +950,7 @@ struct tallyitem
     tallyitem()
     {
         nAmount = 0;
-        nConf = INT_MAX;
+        nConf = std::numeric_limits<int>::max();
     }
 };
 
@@ -1002,7 +1002,7 @@ Value ListReceived(const Array& params, bool fByAccounts)
             continue;
 
         int64 nAmount = 0;
-        int nConf = INT_MAX;
+        int nConf = std::numeric_limits<int>::max();
         if (it != mapTally.end())
         {
             nAmount = (*it).second.nAmount;
@@ -1021,7 +1021,7 @@ Value ListReceived(const Array& params, bool fByAccounts)
             obj.push_back(Pair("address",       address.ToString()));
             obj.push_back(Pair("account",       strAccount));
             obj.push_back(Pair("amount",        ValueFromAmount(nAmount)));
-            obj.push_back(Pair("confirmations", (nConf == INT_MAX ? 0 : nConf)));
+            obj.push_back(Pair("confirmations", (nConf == std::numeric_limits<int>::max() ? 0 : nConf)));
             ret.push_back(obj);
         }
     }
@@ -1035,7 +1035,7 @@ Value ListReceived(const Array& params, bool fByAccounts)
             Object obj;
             obj.push_back(Pair("account",       (*it).first));
             obj.push_back(Pair("amount",        ValueFromAmount(nAmount)));
-            obj.push_back(Pair("confirmations", (nConf == INT_MAX ? 0 : nConf)));
+            obj.push_back(Pair("confirmations", (nConf == std::numeric_limits<int>::max() ? 0 : nConf)));
             ret.push_back(obj);
         }
     }
diff --git a/src/headers.h b/src/headers.h
index fd086faee8..b6903fe93e 100644
--- a/src/headers.h
+++ b/src/headers.h
@@ -21,9 +21,6 @@
 
 // Include boost/foreach here as it defines __STDC_LIMIT_MACROS on some systems.
 #include <boost/foreach.hpp>
-#ifndef __STDC_LIMIT_MACROS
-#define __STDC_LIMIT_MACROS // to enable UINT64_MAX from stdint.h
-#endif
 
 #if (defined(__unix__) || defined(unix)) && !defined(USG)
 #include <sys/param.h>  // to get BSD define
@@ -44,7 +41,6 @@
 #include <stdlib.h>
 #include <time.h>
 #include <math.h>
-#include <limits.h>
 #include <float.h>
 #include <assert.h>
 #include <iostream>
diff --git a/src/key.h b/src/key.h
index 3f4b72d2d3..94ec55228e 100644
--- a/src/key.h
+++ b/src/key.h
@@ -178,13 +178,14 @@ public:
 
     bool Sign(uint256 hash, std::vector<unsigned char>& vchSig)
     {
-        vchSig.clear();
-        unsigned char pchSig[10000];
-        unsigned int nSize = 0;
-        if (!ECDSA_sign(0, (unsigned char*)&hash, sizeof(hash), pchSig, &nSize, pkey))
+        unsigned int nSize = ECDSA_size(pkey);
+        vchSig.resize(nSize); // Make sure it is big enough
+        if (!ECDSA_sign(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], &nSize, pkey))
+        {
+            vchSig.clear();
             return false;
-        vchSig.resize(nSize);
-        memcpy(&vchSig[0], pchSig, nSize);
+        }
+        vchSig.resize(nSize); // Shrink to fit actual size
         return true;
     }
 
diff --git a/src/main.cpp b/src/main.cpp
index 052701e5fc..e2f3cc9f84 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -366,7 +366,7 @@ bool CTransaction::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs, bool* pfMi
         return DoS(100, error("AcceptToMemoryPool() : coinbase as individual tx"));
 
     // To help v0.1.5 clients who would see it as a negative number
-    if ((int64)nLockTime > INT_MAX)
+    if ((int64)nLockTime > std::numeric_limits<int>::max())
         return error("AcceptToMemoryPool() : not accepting nLockTime beyond 2038 yet");
 
     // Safety limits
@@ -1875,7 +1875,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         }
 
         // Ask the first connected node for block updates
-        static int nAskedForBlocks;
+        static int nAskedForBlocks = 0;
         if (!pfrom->fClient &&
             (pfrom->nVersion < 32000 || pfrom->nVersion >= 32400) &&
              (nAskedForBlocks < 1 || vNodes.size() <= 1))
diff --git a/src/main.h b/src/main.h
index 7f8da4e898..67524ef4be 100644
--- a/src/main.h
+++ b/src/main.h
@@ -258,17 +258,17 @@ public:
 
     CTxIn()
     {
-        nSequence = UINT_MAX;
+        nSequence = std::numeric_limits<unsigned int>::max();
     }
 
-    explicit CTxIn(COutPoint prevoutIn, CScript scriptSigIn=CScript(), unsigned int nSequenceIn=UINT_MAX)
+    explicit CTxIn(COutPoint prevoutIn, CScript scriptSigIn=CScript(), unsigned int nSequenceIn=std::numeric_limits<unsigned int>::max())
     {
         prevout = prevoutIn;
         scriptSig = scriptSigIn;
         nSequence = nSequenceIn;
     }
 
-    CTxIn(uint256 hashPrevTx, unsigned int nOut, CScript scriptSigIn=CScript(), unsigned int nSequenceIn=UINT_MAX)
+    CTxIn(uint256 hashPrevTx, unsigned int nOut, CScript scriptSigIn=CScript(), unsigned int nSequenceIn=std::numeric_limits<unsigned int>::max())
     {
         prevout = COutPoint(hashPrevTx, nOut);
         scriptSig = scriptSigIn;
@@ -284,7 +284,7 @@ public:
 
     bool IsFinal() const
     {
-        return (nSequence == UINT_MAX);
+        return (nSequence == std::numeric_limits<unsigned int>::max());
     }
 
     friend bool operator==(const CTxIn& a, const CTxIn& b)
@@ -308,7 +308,7 @@ public:
             str += strprintf(", coinbase %s", HexStr(scriptSig).c_str());
         else
             str += strprintf(", scriptSig=%s", scriptSig.ToString().substr(0,24).c_str());
-        if (nSequence != UINT_MAX)
+        if (nSequence != std::numeric_limits<unsigned int>::max())
             str += strprintf(", nSequence=%u", nSequence);
         str += ")";
         return str;
@@ -468,7 +468,7 @@ public:
                 return false;
 
         bool fNewer = false;
-        unsigned int nLowest = UINT_MAX;
+        unsigned int nLowest = std::numeric_limits<unsigned int>::max();
         for (int i = 0; i < vin.size(); i++)
         {
             if (vin[i].nSequence != old.vin[i].nSequence)
diff --git a/src/net.cpp b/src/net.cpp
index 7d2f18b2d0..9b8dbe11e8 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -249,8 +249,8 @@ bool Lookup(const char *pszName, vector<CAddress>& vaddr, int nServices, int nMa
             else
                 pszColon[0] = 0;
             port = portParsed;
-            if (port < 0 || port > USHRT_MAX)
-                port = USHRT_MAX;
+            if (port < 0 || port > std::numeric_limits<unsigned short>::max())
+                port = std::numeric_limits<unsigned short>::max();
         }
     }
 
@@ -1488,7 +1488,7 @@ void ThreadOpenConnections2(void* parg)
         // Choose an address to connect to based on most recently seen
         //
         CAddress addrConnect;
-        int64 nBest = INT64_MIN;
+        int64 nBest = std::numeric_limits<int64>::min();
 
         // Only connect to one address per a.b.?.? range.
         // Do this here so we don't have to critsect vNodes inside mapAddresses critsect.
diff --git a/src/protocol.cpp b/src/protocol.cpp
index f46570e21c..27efb8f293 100644
--- a/src/protocol.cpp
+++ b/src/protocol.cpp
@@ -223,7 +223,7 @@ bool CAddress::IsValid() const
     if (memcmp(pchReserved, pchIPv4+3, sizeof(pchIPv4)-3) == 0)
         return false;
 
-    return (ip != 0 && ip != INADDR_NONE && port != htons(USHRT_MAX));
+    return (ip != 0 && ip != INADDR_NONE && port != htons(std::numeric_limits<unsigned short>::max()));
 }
 
 unsigned char CAddress::GetByte(int n) const
diff --git a/src/qt/optionsmodel.cpp b/src/qt/optionsmodel.cpp
index efc216dab8..eef91db5ba 100644
--- a/src/qt/optionsmodel.cpp
+++ b/src/qt/optionsmodel.cpp
@@ -101,7 +101,7 @@ bool OptionsModel::setData(const QModelIndex & index, const QVariant & value, in
         case ProxyPort:
             {
                 int nPort = atoi(value.toString().toAscii().data());
-                if (nPort > 0 && nPort < USHRT_MAX)
+                if (nPort > 0 && nPort < std::numeric_limits<unsigned short>::max())
                 {
                     addrProxy.port = htons(nPort);
                     walletdb.WriteSetting("addrProxy", addrProxy);
diff --git a/src/qt/transactionrecord.cpp b/src/qt/transactionrecord.cpp
index 77c5a01260..53cd35b2da 100644
--- a/src/qt/transactionrecord.cpp
+++ b/src/qt/transactionrecord.cpp
@@ -187,7 +187,7 @@ void TransactionRecord::updateStatus(const CWalletTx &wtx)
 
     // Sort order, unrecorded transactions sort to the top
     status.sortKey = strprintf("%010d-%01d-%010u-%03d",
-        (pindex ? pindex->nHeight : INT_MAX),
+        (pindex ? pindex->nHeight : std::numeric_limits<int>::max()),
         (wtx.IsCoinBase() ? 1 : 0),
         wtx.nTimeReceived,
         idx);
diff --git a/src/serialize.h b/src/serialize.h
index d3f6b7d703..98b69aa228 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -19,16 +19,8 @@
 #include <boost/tuple/tuple_comparison.hpp>
 #include <boost/tuple/tuple_io.hpp>
 
-#if defined(_MSC_VER) || defined(__BORLANDC__)
-typedef __int64  int64;
-typedef unsigned __int64  uint64;
-#else
 typedef long long  int64;
 typedef unsigned long long  uint64;
-#endif
-#if defined(_MSC_VER) && _MSC_VER < 1300
-#define for  if (false) ; else for
-#endif
 
 #ifdef WIN32
 #include <windows.h>
@@ -197,8 +189,8 @@ template<typename Stream> inline void Unserialize(Stream& s, bool& a, int, int=0
 inline unsigned int GetSizeOfCompactSize(uint64 nSize)
 {
     if (nSize < 253)             return sizeof(unsigned char);
-    else if (nSize <= USHRT_MAX) return sizeof(unsigned char) + sizeof(unsigned short);
-    else if (nSize <= UINT_MAX)  return sizeof(unsigned char) + sizeof(unsigned int);
+    else if (nSize <= std::numeric_limits<unsigned short>::max()) return sizeof(unsigned char) + sizeof(unsigned short);
+    else if (nSize <= std::numeric_limits<unsigned int>::max())  return sizeof(unsigned char) + sizeof(unsigned int);
     else                         return sizeof(unsigned char) + sizeof(uint64);
 }
 
@@ -210,14 +202,14 @@ void WriteCompactSize(Stream& os, uint64 nSize)
         unsigned char chSize = nSize;
         WRITEDATA(os, chSize);
     }
-    else if (nSize <= USHRT_MAX)
+    else if (nSize <= std::numeric_limits<unsigned short>::max())
     {
         unsigned char chSize = 253;
         unsigned short xSize = nSize;
         WRITEDATA(os, chSize);
         WRITEDATA(os, xSize);
     }
-    else if (nSize <= UINT_MAX)
+    else if (nSize <= std::numeric_limits<unsigned int>::max())
     {
         unsigned char chSize = 254;
         unsigned int xSize = nSize;
diff --git a/src/uint256.h b/src/uint256.h
index b6132822c5..d3da1f26d2 100644
--- a/src/uint256.h
+++ b/src/uint256.h
@@ -11,16 +11,8 @@
 #include <string>
 #include <vector>
 
-#if defined(_MSC_VER) || defined(__BORLANDC__)
-typedef __int64  int64;
-typedef unsigned __int64  uint64;
-#else
 typedef long long  int64;
 typedef unsigned long long  uint64;
-#endif
-#if defined(_MSC_VER) && _MSC_VER < 1300
-#define for  if (false) ; else for
-#endif
 
 
 inline int Testuint256AdHoc(std::vector<std::string> vArg);
diff --git a/src/util.cpp b/src/util.cpp
index ef276e5103..80ce404593 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -133,7 +133,7 @@ uint64 GetRand(uint64 nMax)
 
     // The range of the random source must be a multiple of the modulus
     // to give every possible output value an equal possibility
-    uint64 nRange = (UINT64_MAX / nMax) * nMax;
+    uint64 nRange = (std::numeric_limits<uint64>::max() / nMax) * nMax;
     uint64 nRand = 0;
     do
         RAND_bytes((unsigned char*)&nRand, sizeof(nRand));
diff --git a/src/util.h b/src/util.h
index d9a0841a61..9fe95e37fd 100644
--- a/src/util.h
+++ b/src/util.h
@@ -25,19 +25,8 @@
 #include <openssl/ripemd.h>
 
 
-#if defined(_MSC_VER) || defined(__BORLANDC__)
-typedef __int64  int64;
-typedef unsigned __int64  uint64;
-#else
 typedef long long  int64;
 typedef unsigned long long  uint64;
-#endif
-#if defined(_MSC_VER) && _MSC_VER < 1300
-#define for  if (false) ; else for
-#endif
-#ifndef _MSC_VER
-#define __forceinline  inline
-#endif
 
 #define loop                for (;;)
 #define BEGIN(a)            ((char*)&(a))
@@ -53,7 +42,7 @@ typedef unsigned long long  uint64;
 #define snprintf my_snprintf
 
 #ifndef PRI64d
-#if defined(_MSC_VER) || defined(__BORLANDC__) || defined(__MSVCRT__)
+#if defined(_MSC_VER) || defined(__MSVCRT__)
 #define PRI64d  "I64d"
 #define PRI64u  "I64u"
 #define PRI64x  "I64x"
@@ -84,11 +73,7 @@ T* alignup(T* p)
 #ifdef WIN32
 #define MSG_NOSIGNAL        0
 #define MSG_DONTWAIT        0
-#ifndef UINT64_MAX
-#define UINT64_MAX          _UI64_MAX
-#define INT64_MAX           _I64_MAX
-#define INT64_MIN           _I64_MIN
-#endif
+
 #ifndef S_IRUSR
 #define S_IRUSR             0400
 #define S_IWUSR             0200
@@ -474,15 +459,6 @@ inline bool GetBoolArg(const std::string& strArg)
 
 
 
-inline void heapchk()
-{
-#ifdef WIN32
-    /// for debugging
-    //if (_heapchk() != _HEAPOK)
-    //    DebugBreak();
-#endif
-}
-
 // Randomize the stack to help protect against buffer overrun exploits
 #define IMPLEMENT_RANDOMIZE_STACK(ThreadFn)     \
     {                                           \
diff --git a/src/wallet.cpp b/src/wallet.cpp
index 87f5dfd659..c6f5795c0b 100644
--- a/src/wallet.cpp
+++ b/src/wallet.cpp
@@ -782,7 +782,7 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe
 
     // List of values less than target
     pair<int64, pair<const CWalletTx*,unsigned int> > coinLowestLarger;
-    coinLowestLarger.first = INT64_MAX;
+    coinLowestLarger.first = std::numeric_limits<int64>::max();
     coinLowestLarger.second.first = NULL;
     vector<pair<int64, pair<const CWalletTx*,unsigned int> > > vValue;
     int64 nTotalLower = 0;