I have to agree with Russ. The fact of the matter is, that unless you have something very important you need to save (which you have already stated you don't), and in a lot of cases where you DO need to save something, it's much easier, much less time consuming, and makes things much faster to just reformat. Russ has outlined most of the steps needed, but not knowing what your technical level is, I will add a couple of notes.
For step A2: If this is necessary, especially with a secondary network card (not built into the motherboard) make sure you turn off the power on the computer. You do NOT want to unplug the power cord. touch the metal on the case before touching any of the boards in the machine.
If you get stuck anywhere, or need anymore help, there are several people here capable of helping out, just give us as many details as possible.
Good luck!
For step A2: If this is necessary, especially with a secondary network card (not built into the motherboard) make sure you turn off the power on the computer. You do NOT want to unplug the power cord. touch the metal on the case before touching any of the boards in the machine.
If you get stuck anywhere, or need anymore help, there are several people here capable of helping out, just give us as many details as possible.
Good luck!