I have just created a fresh install of Windows 7 (64-bit), and then Visual C# Express 2010 Beta 2 (none of the other Visual Studio 2010 products have been installed). Loading a project created under Visual C# Express 2010 Beta 2 on Vista 32-bit and debugging results in an error,
"The program can't start because MSVCR100.dll is missing from your computer. Try reinstalling the program to fix this problem."
NB: There are a number of feedback items that mention this error after uninstalling VS2010, but this is after installing directly onto a fresh OS - it seems that the required file was never installed in the first place (maybe a 64-bit issue?)