Sir Kenyth, I am so sorry for you! That sucks majorly.
The trouble with the Ebay rating system is that it's so abused. A person will get a contingent of friends to "run the ratings up" on him or her and Ebay has no method of detecting or correcting for this. In short, the rating is about as good as cheap toilet paper. It can work, but often you'll find yourself in a position you DON'T want to be in.
So sorry to hear about the computer, man. Hopefully, you'll find another buyer for your old system.
Cheers,