Sudenly all my executables and shortcuts will not work and I get the error "This file does not have a program associated with it for performing this action. Create an asociation in the Folder Options control panel" when I try to run them. There are exceptions like the Inernet Explorer desktop icon which runs normally. However if I run iexplore.exe directly I get the same error.
I am working around this at the moment by right-clicking and using "Run as..." which will let me run anything normally so far.