XPS 8500 power off issues

Amen brother. Don't mean to hijack your thread but I've got an unresolved complaint myself, and am feeling pretty ticked off at Dell right now as well. I too am having a problem with an XPS-8500 (still under warranty). Seems a LOT of people are having problems with XPS-8500's... :-( The thing won't power off after I shut it down. Everything appears to shut down, except the motherboard, video card, cpu, and fans all remain powered ON. I have to hold down the power switch to turn it off. Happens in both Win 7 AND Linux. Have tried upgrading the BIOS and reinstalling Win7 to a spare hard drive and it made no difference. Tech support has pretty much blown me off. The email I received from tech support gave me steps to resolve my "error while waking up from the Sleep Mode". Say what? That's not even remotely related to the issue I am having. Now today I checked the status of this support request and it says "closed". Well golly gee Dell, thanks a lot for nothing. I guess if someone does respond, they'll be telling me to use phone support (India) with people who only know how to tell customers to "reinstall Windows"- (did that) and upgrade the BIOS (did that too). I've had pretty good luck with Dell, I have 3 of them, but I never needed help before for what is obviously a faulty power supply or motherboard problem. I'm thinking my next system might be an but I don't know if their tech support is any better. This problem is really giving me pause about ever buying another Dell though.