It's not a laptop. It's a Compaq desktop machine. If you have the exact model number of your machine you can usually google it and find a site that tells you the motherboard make and specs. I would doubt the dvd would be a problem but a search of the make and model shouldn't be that hard to do.
We didn't do any kind of rollback. Just a total reformat of the hard drive and a clean install of a new operating system. There are workarounds for some of the issues. But I did learn the hard way, better to research the motherboard and chipset first. We finally got her's up and running on xp pro. The wife is happy now and won't be using vista for a long time. Microsoft is going to stop producing xp in order to push the vista transition. Next payday I think I'm going to order 3 copies of xp pro just to have for future builds and upgrades.