This tutorial will explain on:
If you are running 32 Bit operating system before and were intrigued to install 64 bit OS to improved performance of your computer, then maybe you are having problems debugging your Visual Studio .NET source code.
I am once having this issue which stops me from debugging all of my VB.NET 2008 source code after I installed Windows 7 64 bit.
Currently Microsoft’s don’t have plan in fixing this issue. So, to solve this problem, open your Visual Studio project.
Once you change the “Target CPU” you will be able to debug your project in 64 bit OS.