Fried Computer Options

[Heewee]

Okay, so the computer at my dad's house had some pretty nasty viruses on it and the whole thing had been screwed up for awhile. I wanted to reformat the computer and start all over but when I went to do that, it wouldn't let me because some of the drivers weren't working correctly. The message said to find the defected drivers and disable them. I accidentally deleted a few essential drivers and I didn't know that they were essential until I tried to restart the computer. Now, the computer won't even boot up, I just get a screen that says it can't start the computer because a driver that is needed to start the computer is missing. It says that I can try installing the driver through the set-up CD but I have searched high and low and can't find it. I'm not sure how to fix this problem. The only answer I can think of is calling HP and asking them to send another one. However, I don't want to go through that mess if I don't have to and even if I did do that, they might not even give me a new one. Any suggestions would be greatly appreciated.