Unfortunately, you've told us nothing about your computer or how the virus got installed so we're simply guessing at what might help. Things like operating system, laptop or desktop, make and model, plus the name of the virus you have, would surely get us started in the right direction.
Still, here are a few suggestions. If you have a type of ransomeware, then our solution here is to wipe the drive and use recovery software back to it's factory condition. (Ransomware asks for payment to give you a key to unlock the encryption on your files. It usually doesn't work, so don't pay.)Then reinstall all your programs, personal files, pictures, etc. using your backups. We've learned that making backups is the single most important things in general computing.
Of course, if it's not ransomeware, then you can certainly run a full system scan with your antivirus, or install a different one and run the scan using that.. There's a free version of Avira at the link below that might get it done.
Once that's done, then please use the link below and follow all the steps to the letter. It should help remove any other malware you might have installed.
“Expand” the post titled: "Please try this" at the link below:
Hope this helps.
Last week all my .jpg file has extra extension and it converted into .jpg.mp3.
Please help to remove this virus and to convert all my image files back to normal. And also suggest which kind of sites contain these serious kind of virsuses and malwares.