I am building a new computer and I want to use the hard drive from my old one in the new one. How do I wipe my old drive completely so that I can just take it out of the old computer and stick it in the new one?
You don't have to format it to use it in the new system. When you boot to the OS install disk, you can format and partition your hard drive when you start the new OS installation. But, if just "want" to do it before hand, simply insert the OS install disk into the computer you have now, start the install program, use it to format and partition the drive, then exit the install program.