Are there any known issues with visual studio and code being swapped between projects?

I had a project running in VS2008 and when i went back to it, the code from another project had been swapped in the Program.cs class. I havent made any mistakes, im not talking about some code- i mean the whole project had been swapped out. Its as if the .proj files or .soln files had been swapped from their project folders???

EDIT

Ive restarted laptop, opened the code again and its still showing the wrong code BUT when i execute it, its the right code?!?!?!