On 64-bit operating systems, .NET Framework supports both WOW64 (32-bit on 64-bit computers) and native 64-bit processing. Ensure you download the correct "x64" or "x86-x64" combined package. The 64-bit version of .NET Framework 4.0.3 (NDP40-KB2600211-x86-x64.exe) is specifically designed to work with Windows 7 64-bit.
This provides the necessary Servicing Stack Update (SSU) to handle new update packages. net framework 403019 windows 7 64 bits extra quality