How do I reset my settings?

How do I reset my Computer to factory settings? (Do I need a disk to reinstall my computer?)?

• Recently I got this virus thing on my computer which I managed to get rid of. However, I had to reset my computer, in a way. I still have all of my programs but most of them aren't working how they were before. I've decided I'd like to reset my computer back to the factory settings but my main question is if once I do, I'll need some disks or software that came with the computer. If so, then I don't think I will since I'm almost sure I don't have them. But if you can reset your computer and get it working without disks, then I will. (I don't mean disks for programs, but the computer itself.)

• Answer:

  If you don't have the CDs there's sometimes a hidden recovery partition on computers. When you turn the computer on do you ever see a message that says something like "press F11 to start system recovery" or along those lines. If you do then give it a shot because it should just restore it from that hidden partition if there is one. If not then yeh, you'll need the CDs.