Reinstalling XP home without full install disk

I was given a couple of Dell computers. I don't have a restore disk. However, the key is written on the outside of the puters. They are........
2.6 mghz
512 megs of ram
80 gig HD
I have a Win 98 disk and an upgrade XP disk.
The computers get worse everyday, and I need to reinstall windows.
I have used the Win 98SE and the upgrade disk to install XP on my gaming machine and it works very good. It evens runs some old games that won't work on the XP Dells.
My question is...if I reinstall XP on the Dells will I be able to use the key that came with the machines, or will the upgrade disk only work with the key that came with it.???
Can I just try reinstalling with the upgrade disk only and the Dell key???
After I back up the dell's data should I format the HD first??
I know this seems like a really simple question, but I have searched everywhere and really have not found a good answer.
Thanks for having a place to go and research before I go messing with a puter lol

 

Hi I think you would probably have an issue with the EULA on this. Im not great with legal stuff, perhaps someone else can help with that.

Some xp discs can only be used with a specific type of licence for example an ActionPack XP CD will only let you instal with an actionpack license.

If you have a valid xp license MS may be able to provide you with a disc.

Matt

 

http://www.microsoft.com/windowsxp/home/eula.mspx
1.1 Installation and use. You may install, use, access, display and run one copy of the Software on a single computer, such as a workstation, terminal or other device ("Workstation Computer"). The Software may not be used by more than one processor at any one time on any single Workstation Computer.

9. UPGRADES. To use Software identified as an upgrade, you must first be licensed for the software identified by Microsoft as eligible for the upgrade. After upgrading, you may no longer use the software that formed the basis for your upgrade eligibility.