It wasn't just luck - it was the power supply. I should have put 2 & 2 together when it crashed during standby mode too. I replaced it with a 500W PSU, and not only have the crashes stopped, the temps are all down 5-10 degrees C as a result of the large fan in the PSU.
Corporate culture never ceases to amaze me. I know the market is competitive, and margins are razor thin. But this "me too" behavior of the PC manufacturers (Gateway, HP, Dell, etc) - where they seem to place the highest premium on price - has led to the manufacture of computers that are buggy, break WAY too soon, and are looked at as commodities. My last - and I do mean LAST - HP laptop died in only 18 months because the heat generated by the CPU eventually fried the wlan card and then the mb. Did HP stand behind it like they do their printers? No, because ink is what drives that model. There is no ink cash-cow when they sell a laptop.
And take the DX4300 we bought. Nice case, decent specs, decent performance. Price was fine. But it is always the little things that truly define a customer experience, and in this case one of the "littlest" things was the power supply. Seriously, 300W is too small for a system like this, and the one that was included is inadequate on every level. So we paid, what, around $700? Even if they pass the cost on to us, what would it add to the price to put in a PSU that would do the job adequately for 3-5 years? $20-30 tops. I would have paid that in a heartbeat. What would our impression of Gateway have been? Would we be likely to buy again? And to recommend Gateway to friends who would have no idea how to build their own system? Was the savings in PSU cost worth creating a bad customer experience? Or are they so jaded that they assume that all their competitors are building the same boxes of crap too? There is a reason that Apple customers are willing to pay more, and it starts with the little things...
I bought this system for the convenience, and I trusted that the components were selected with some care. (I've built my own before - it is fun, but it takes time.) My mistake - the Gateway of today is not the Gateway from whom I bought my first mail-order computer 20 or so years ago.
Good luck with your complaint, and thanks for helping me figure out the problem with my DX4300.