See if it will boot. I suggest getting a low-level format tool or a tool that will wipe out your whole harddrive including the viruses. Then create partitions using fdisk or a partition program and then format each partition. Some os's let you format the partitions in the install program. Its up to you if you want to format with fdisk or the install program.
Then install the os. Make sure before you install it, that there is no problems or viruses let on your hard drive. If there is, it could be a problem for you down the road.
Hope this helps!