Password needed when opening exe files

[jongeeone]

A mates PC had a virus, after removal it destroyed file associations. CCleaner fixed this, however when running .exe files it requires user name and password every time.

Any input?

Thanks

 

[jongeeone]

Running XP.
AVG removed the virus which come through a facebook app. All trojans are gone, it just then stoped any files from opening. CCleaner fixed this, it just needs a password to running any .exe file now.

I'll give combofix a go.