Hi,
While a normal format will get things going for you, I always for a new format recommend the Dban program
HERE for best results. Be very careful you don't erase some other disk on your computer, so it might be a good idea if you have hard drives you don't want to erase, that you disconnect them.
If on the other hand, you want to do a simple (not as comprehensive) format, just put your OS disk in the CDRom, boot up and it will prompt you to format and load the OS. Don't forget to load SP2 (some OS disks have it already in there) and your chipset drivers when done along with other drivers you might need.
Post back with questions/concerns.