Should I Reinstall Vista on my PC?

Hey guys, i have been running windows vista on my Dell pc for about 3 years now. Recently, after my McAfee Anti-Virus expired, i caught a pretty nasty virus. It would not let me install any .exe files. And later would no let me open them either. After going into safe mode, i was able to run a MalwareBytes scan and terminate part of this virus. This morning when I turned on my PC it went directly to the Windows Recovery Menu with the user, "Other User". I could not to log in to it so i tried safe mode, last known configuration, and starting it normally. It would not work. I does not boot properly anymore. I was looking through my discs and i found- Dell Drivers and Utilities, "Operating System" Reinstalliation DVD, and Audigy Sound Blaster. Now I need your help for the next part. Should I reinstall Vista? I have now important files on my PC which I would like to back up. And if so how? Can someone please help! Thank you for your time. =)