I get this error when I try to load a VS 2008 project from TFS source control:
The project file has been moved, renamed or is not on your computer
TFS works like most source control packages: It remembers what it has put on your computer so that when you "Get Latest" it only has to get the chnages since your last "Get" instead of having to get absolutely everything.
This has one caveat: If you delete or rename the local files on your disk, TFS won't know that you have done this, and it will still think they are where it left them.
If you then "Get Latest" it will not bother to update the missing files.
You are then likely to get all kinds of "missing file" errors, from TFS and any other tools that look for the files.
To get around it, you need to:
If you have any locally-changed (writable) files, then be careful. There is a second option that will overwrite these, losing your changes. But you have the backup, so you should be safe. It's generally better to tick this option as well to make sure that all your source code is completely up to date. (But obviously only if you don't mind losing any local changes!)
When you OK, this will forcibly get all the files in the project to your local drive, and should correct the problem.