Hope this isn't going to be your main desktop rig. It's pretty old.
I do agree with what many posted here, You are better off doing a simple format if possible. Dell units starting from that era also began rolling out restore images on a second partition on the main drive. Formatting could cause you to lose that partition.
If you absolutely want to nuke the drive then give DBAN a shot. It is by far, the best free solution for multi-pass wiping of drives.
http://www.dban.org/