ATI do seem unreliable imo, but I think its the card makers economising on the heatsinks, I had the same problem with 9800pros twice, seems my original card had a WAY too small heatsink on it, exactly the same symptoms on the replacement too, the first died totaly, the one that finaly failed like yours originaly used to overheat within minutes of running any high end games and break up/artifact or cause a severe system crash that messed up windows, I kept that one going reliably for over a year after the initial problems by adding a huge aftermarket heatsink to it, the original heatsinks would get so hot you could almost burn your fingertips on it, thats what gave me the clue (no **** Sherlock!
), on the other hand I have had several Nvidia cards and no problems so far (touchwood), like Joel I can only make assumptions based on what happened to me, IMO Radeons at least, have undersized heatsinks fitted for some reason, Nvidia don`t overheat or wear out afaik, I still have a GeForce4mx running the multimedia system downstairs, thats OLD now, but it never gives any trouble, on the other hand Joel hasn`t had any problems with his cards...maybe the brand he bought use bigger heatsinks.
Windows: 32 bit extension/graphical shell for a 16bit patch to an 8bit OS originally coded for a 4bit CPU, written by a 2bit company that can't stand 1bit of competition, now available in 64bits.