Ah I get you now. Sorry, I didn't know you couild buy updates from other operating systems, though I'd have to be a pretty big update to go from win 98 to XP.
Found this though that explains i am wrong and that you can
As a precaution, you could try running autorun, since it might have a boot up sequence which I think it does.
To do this though, you'll have to be able to see your cd rom drive in the device manager (which you might be able to do and as long as it's llisted in here, its installed right...its just windows being crap
Right click on My Computer, and go to Properties.
Go to the Device Manager Tab.
Open the Cd rom branch from the list
Select the cd rom, and go to properties, and choose settings.
Turn on the auto insert notification option.
Click okay, and restart windows.
Hopefuly this will work, and even though its not viewable in Explorer (might be somethnig to do with how its managed by windows), it'll hopefully boot from the cd rom and view it automatically when you place the disc in.
If not, try going to 'run' in the startmenu, and type:
x:\autorun (x being the cd drive letter, which it's suppsoed to be)
I hope this helps