Massive problem with loading EXE files

[tepster]

Hey, after messing about with a few programs, possibly malicious, every exe i try to load doesn't work. Ive tried Mirc, steam, stepmania, every single program i have wont load.

The error is,

The file "blahblah.exe" cannot be found in C:\program files\blahblah\blahblah.exe, the file destination is either corrupt or files are messing
The files ARE there, and im sure no other file has been misplaced/deleted. I mean, surely its impossible that every program file i have is losing a file?

Has any1 heard/been in the same situation and knows what to do?

Thanks in advance

 

[tepster]

If it helps, my internet explorer doesnt work and comes up with the same error

However, if i click on a saved webpage, it loads up fine. Any ideas :/?

 

[IronDuke]

You could do a system restore to before you did your messing.

 

[tepster]

Forgot to mention i run windows 2000, i dont think i can?

Or maybe i can... im not sure :/