check the capacitors, strip the system down and try reseating the heatsink, also confirm you have the latest bios revision

Cubsfan,
Eerily enough I have been having the same exact problem, which started maybe a day or two after you posted. When I first opened it up the heat sink and vents around it were thoroughly choked with dust, which I have since removed without helping the problem too much. It was shut down almost all of today, and I just recently played with the sink a little to get it up and running now, but I don't trust that I have fixed because it's the second or third time I've done it and don't particularly want to risk another long shutdown by testing right now. Have you had any success in fixing the problem by Mark's suggestions or anything else?

Thanks.

Yeah, it seems to have been fixed. First Dell replaced my motherboard, but that didn't solve the problem. Then I checked the memory and some of the non-essential devices by first removing them and seeing if I could get a stable configuration, but to no avail. Finally, Dell sent me a new processor and heat sink, and once those were installed, the problem seems to have gone away. I talked to someone who works in computer repair who told me they had the same problem, and replacing the processor and heat sink finally fixed it.

I'm not entirely sure that my computer is fixed, due to the random nature of the problem I was originally having, but I have had no problems since Thursday (when the new processor and heat sink were installed), I'm optimistic. The fan on this particular machine had been very loud since I purchased it, (even when the computer was running fine) and since Thursday, it's been very quiet.

I was lucky, since I'm still under warranty I wasn't out any money to replace these components. If you're having problems similar to mine, replacing the processor might be the way to fix them. I hope this information helps.

The fan is a very common problem with the GX280's, I probably run into it about 2-3 times a week.  At this point, I don't even bother going into a lot of detail when I send the info in, just say that the fan took off like a helicopter propeller and in an hour or two I get an e-mail that they're sending me out parts.

One machine acted quite the same as yours and finally took Dell sending someone out with a ton of spare parts, and now I'm on the second one that is not working despite the MB and memory they sent.  I'll see if I can convince gold support to send me a processor and heat sink this time.  Wish  that Unisys guy had waited for me so I could find out what part it turned out to be. 

It's been a couple of weeks now since the replacement, and I have had NO problems since then. The fan hasn't done much more than purr in two weeks, and while I haven't exactly been killing it with work, it wasn't taking much more than checking my email and listening to a CD at the same time to send it into delirium before the new processor/heat sink. If you can convince them to replace yours, do it, I think it will work.

On a side note, if this is such a common problem, I would think that technical support would have been alerted about it at some point in time, but it still took me five calls to get the processor replaced, and even then it was just a lucky guess by the operator after I had told him I did not want to dismantle my computer piece by piece to find the culprit until we had tried all of the obvious options. On the whole, tech support is pretty good, but in this case... Ok, mini-rant over. :-).

Message Edited by cubsfanjkw on 06-21-200610:49 AM

im not convinced that would be because of the processor, why would a processor cause the fan to overspin unless it was overheating due to lack of cooling? the reason the motherboard was replaced is because sometimes the cpu temp sensor gets damaged and the motherboard controls the speed of it, the heatsinks have known issues if you give them the part numbers. In those cases you had the cpu AND HSF replaced it probably only required a HSF

You bring up a good point, and it may be applicable to some of these situations. However, in the case of my system, the system fan would go haywire even when the computer had not run for 24+hours, and would do so immediately at startup, not even reaching the BIOS screen. Of course, such situations occurred randomly, but often. That, coupled with the 'incompatible processor detected' message after random reboots, leads me to believe the processor was partially at fault as well. Replacing the motherboard did not fix the problem, as it was done before the processor and heat sink were replaced. Only after the processor and heat sink were replaced did the problems subside. Since both were replaced at the same time, I cannot be sure that the processor was faulty, however, per the above, I am inclined to believe it was.