The thing is,how much do hope to raise with this sale ?
Without being rude or insulting you,i think most people will be looking for a warranty from a well known retailor such as Pcworld/Novatech/Evesham etc.
Ive been looking recently for a spare system for one of the kids and come across some for around £220.00 with XP Home/Sempron 2800 dvd rewriter etc.
And considering i have just rebuilt a system for under £100,bearing in mind i had the tower and hdd and second hand parts it works brilliantly.I just feel most would like a big name warranty. Though im sure it will sell,the problem is how much you hope to get.