.avi and .mp3 files got converted to jpeg.

Hi Guys,

Last time when i used by friend’s pen drive my comp was attacked by a virus, which converted all my .avi and .mp3 files to jpeg. I cleaned my system with bitdefender and removed all the viruses found. I tried renaming a few files(to check) but i am back to square one. Again the files got converted to jpeg. And 1 more thing , is there any way we can convert the extension of the files in one shot.

Please help me with this.

Thanks

~R