I have copied a VS.Net 2005 C# Solution from a windows 2000 machine, to an XP machine, and worked on it on the XP machine. When I tried to work on the project when it was copied back to the 2000 machine, I got the error message shown above when I tried to open any Form in the Solution.

Error Message "Could not load file or assembly, 'VSlangProj, Version 7.0.3300.0 ...
JasonWHowell
It's ok after all, the problem was that Visual Studio crashed and trashed a directory structure. After a scan disk, everything was working again.