Try the Ebay affilate program, if they don't go through CJ or LinkShare.
Any major PC manufacturer is going to use something like LinkShare of CJ.
Amazon.com sells PCs and they use a homebrew affiliate program. Though the commission is 4% and jumps to 6% once you sell 25 items or so, they limit commission on computer purchases to $25.
If you wanted to consider LinkShare, Dell offers 4% commission on XPS purchases. Personally, I've had trouble getting into their program, even though I don't violate any of their policies!