I want to check the legality of this..

I know there are no lawyers here, I understand that. :)

My question is:

I need a copy of Office XP (2007 is too much of a resource hog for a laptop I am refurbishing for someone).

Now, say I know someone who had XP but then upgraded to 2007 and they do not use Office XP anymore.

I can buy the discs and license off of them and use it on this laptop - correct?

Edit: Just to reiterate, Office XP / 2003 is completely uninstalled or upgraded to 2007 and the person only uses 2007 now.

If it is a retail item, generally, yes.

ref: http://www.michaelstevenstech.com/xpfaq.html#8

If the O2007 version was an upgrade, it depends on keeping the XP license to remain "legal". If it was retail or OEM then the old version can be reused.