its not a heat issue... although i agree they can get hot....
your statement is sorta... counter intuitive if it was a heat problem, the longer it was on, the more heat problem you would have... so your crashing isnt because of heat... from what i believe..
this summer you might see some heat problems... people without air conditioning, and living it pretty warm climates might run into some problems... it didnt happen when they were first released because by the time the mass population got their G5's it was already fall hehe.
but i would suggest to anyone with a G5, who is running off the install that came from the factory, to back up all your stuff, and clean house... format/partition the hard drive, and reinstall your OS.
these computers have all been multicasted the image... and shipped out without much checking to make sure eveything worked out ok...
we do it at work all the time... i work for my highschool when i come home from college, doing misc. computer work for both pc and mac... and we just turn em all on, bring a powebook back to the main data frame, pop it in the uplink, and broadcast the install over the network... then each computer will pick it up and install the new image that we have worked on... which is locked down to keep kids like me from breaking through their security and putting silly backgrounds on their computers lol.
and of course all the G5s at the store will work
if they dont, they send em back... and once you have one that does work, it will always work
hehe