If you don't have DVD-Rom then how would you install windows Xp on Network?
If you've got a license and lost your media, call Microsoft and ask if they can send you a replacement.
If you want to install it without using the CD-ROM: make sure your PCs support PXE, and look for RIS (Remote Installation Services) or WDS (Windows Deployment Services).
Thank you pludi.
I was wondering if one was able to install XP over the network. I'll research your suggestions a bit.