Recovery CD (W98-TP570) needs Window-Key-Nr?

[AndreasR]

I tried to reinstall Windows 98 (Chinese-Taiwan) on a Thinkpad 570 from
the original recovery CD that came with the system. After installation (I believe it formated the C: partition) it askes me to enter the windows product key. However I don't know it! There is no sticker on the machine, and I can't find the original manual anymore that might have it.

I thought the recovery should work without having to enter any keys? Please help!

Andreas

ps. I believe we had registered the thinkpad with IBM when we first bought it many years ago. Would calling up IBM help? Would they know the windows key, given the laptops serial number?