My computer is completely wiped out?

I had accedentally downloaded a virus and wreaked the computer and then used the last known configuration method that worked option and then I wrecked that too because I didn't delete the file when I had the chance.I used roxio start up thing which restores the computer to another date,I had two options and I picked the farthest date back and now my computer doesn't even have a damn start button or the little bar thingy at the bottom,so I tried to copy the enternet explorer to my mp3 player and tryed to get it to open up after I pluged it into my laptop it would say on the mp3 that it was pluged in but the box thingy for the mp3 player didn't show up.the computer does this everytime I try to use it.I want it to work,does anyone know how to fix it?