The W98 ProductKey is generally found on the Windows user manual, the
certificate of authenticity, a sticker on the PC or a sticker on the sleeve
or jewel case the Windows CD came in. The Key also might be available from
the system.
If the system is working in either safe or normal mode:
Open regedit.exe to this key and look in the right pane for the entry
ProductKey:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion
If the system is not working, start the computer with a floppy startup disk.
At the A: prompt, type: C:\Windows\Command\Find /N "ProductKey"
C:\Windows\System.dat
(Note: ProductKey must be typed in upper and lower case letters as shown
and there is a space after: "Find" after: "/N" and after:
"ProductKey"
If the hard drive has been formatted, contact Microsoft at: 1 800 642-7676.

Signature
Regards
Ron Badour, MS MVP for W98
Tips: http://home.satx.rr.com/badour
Knowledge Base Info:
http://support.microsoft.com/default.aspx?pr=kbinfo
> Have old 98 disk, no product key, trying to install to
> used thinkpad and can't get beyond Product key request
> page.
This site im giving you is kind of illegal but since you
own the software, its ok. Since Win98 doesnt use the same
registration system as win XP where theres many
verification checkpoints, multiple users can use the same
cd key. I suggest checking out this site:
www.astalavista.com
Type in 'Windows 98' in search and use one of the sites
in the scroller. No matter what, you will find a key
somewhere in a return.