Hi Onan,
The password should be on a label on the jewel case. If not, go
here and download and run the Belarc advisor. It opens a new browser window with all the relevant software/hardware info you're ever likely to need. Scroll down to
Software Licences and look for your OS. It gives you the CD key there.
Of course you need to do this before formatting, and you can transfer the program between machines if you don't have net access.
I think you said you wanted to use the recovery discs off of one PC on another. I'm pretty certain that you have only 30 days to register XP via the net, [to stop piracy] and this may cause problems..
Someone else can jump in at this point, as I don't need to worry about that with W98..
Cheers
Liam