Download whatever drivers you need and put em on a CD. Would also be a good idea to download Windows XP SP 2 and put it on a CD.
Link to SP 2 download. An unpatched Windows machine directly connected to the Internet can become infected with viruses in a matter of seconds!
Unplug the network cable.
Put the XP disc in, boot off it, let it format the drive as part of the setup process. The CD allows you to delete, create, and format partitions.
Install drivers and SP 2. Create a restricted user for the roommates to use, maybe a power user for you to use. Not a good idea to use an administrator account all the time.
Plug in network cable.