Hi my name is ***** ***** I will be the expert working with you today to help resolve your problem.
what is the operating system you have on the infected pc.
Try to boot to save mode with networking and let me know if you have tried that.
power off the computer wait for 30 seconds keep your finger on the F8 key and turn on the power button and keep tapping the F8 key couple of times, you will see a black screen select safe mode with networking using the arrow key and hit enter. it will load windows.
i am not an expert is file conversion however i can clean your system and make to work again like a normal computer.
are you in windows screen now?
have you tried to clean the virus.
i will open your question to other experts who can do this as i have no expertise in conversion.
What program did you use to back them up?