all my mp3 files suddenly turned into *.mp3.vbs and the size of the files turned into 10 kb,maybe you'l have an idea
Maybe they're some kind of shortcuts. Click Start/Search/Files, and search for *.mp3 in your whole hard drive.
It probably is a virus a VBS one at that. There are viruses around that attack mp3's but usually by deleting them. You'd better virus scan your system thoroughly with a quality antivirus program!
Yeah F-PROT Antivirus for DOS which is free for personal use is very good indeed, it also is the best antivirus I've found for making DOS boot disks to truely eradicate any virus, of course in saying that a powerful command line is needed such as: F-PROT /HARD /ARCHIVE /PACKED /COLLECT /DUMB /AUTO /DISINF /RENAME /DELETE /REMOVENEW /WRAP