Paint.exe

I do not know how but my computer has been attacked by some paint.exe virus it converts all my exe files to system files and makes them hidden with a "v" in-front of the name i.e Word.exe becomes vWord.exe and becomes hidden. I have tried countless full system scans with my Norton 360 but after awhile i find it again all over my computer especially in C:\Users\username\AppData\Roaming. Any one with a solution or help ill appreciate it.