not sure whether the downgrade rights is applicable in the manner you described, but it doesn't hurt to ask.
The partition that you see is the recovery partition for your hdd and another smaller partition contains the recovery media, which can restore the hdd to the condition that it was shipped to you from factory. i.e. with windows and drivers installed.
May this year, be the year of 'DO'!
I am a volunteer, and not a paid staff of Lenovo or Microsoft
according to IBM service the downgrade rights are no longer available. I've purchased a set of the recovery disks and the XP downgrade disk (about $55 US shipped) that would have come with new machines. While there may have been a cheaper solution this guarantees the result i need with a minimum of time. thanks for your help.