Fans always @4400rpm, sleeping while working

Question

I have a 1st generation 20" iMac that has very loud fans and that has recently started going to sleep while I'm working. Needless to say, this is pretty annoying.
I have...
- repaired permissions
- run both Disk Utility and Diskwarrior
- reset the SMU
- reset the PRAM
- checked CPU usage with Activity Monitor (nothing abnormal)
Using X-Resource Graph I see that the CPU temp is a pretty consistant 68.7 Celcius and that the CPU fan is running at 4400 from the moment the machine is turned on.
I called Apple support, who suggested that I bring the computer to the nearest Authorized Service Center, which is an hour's drive (Maine) or purchase Applecare. I understand the benefits of Applecare, but want to make clear that this computer needed a Motherboard replacement straight out of the box (with a refurbed component) and has always had problems. It is also in the serial number range of computers in the iMac G5 power/video extended warranty. It seems unfair that Apple should expect me to drive an hour each way to drop off a computer, and then to be without it while it's being fixed (hard to be a web designer without a computer) when it was broken out of the box.
Does anyone have any advice on software issues that I may have missed?

Answer 1

Today, after continuous problems with the iMac going to sleep, and after noticing that some of the logic board transistor's had bulging tops, I re-ran the Apple Hardware Test and got an error for the logic board - 2GMC/3/15: built-in
Broke down and ordered Applecare. Called Apple support and the rep said, and I kid you not, "Oh, you totally have to replace the logic board." Unfortunately, I have to wait for the Applecare package to arrive in the mail and then arrange for someone to come and repair it. Oh yeah, and it usually only takes 5 days or so to get an appointment.
Wait! I'm relying on this computer, which has NEVER worked properly, for my business. I just paid $169 for Applecare to have it repaired more conveniently, even though it's in warranty, and now I have to wait for the Applecare package to arrive (estimated 5 days) and then call for an appointment.
If a vs.1 iMac G5 user has a bad logic board (bad power supplies, bad thermal sensors, etc.) Apple should pick the computer up and deliver it back repaired. If the computer needs to have its logic board replaced more than once, the computer should be replaced. Why can't Apple just do what is right, acknowledge that the vs. 1 G5 iMac had serious problems, and repair them at their expensive and at their customer's convenience.
This is leaving a seriously bad taste in my mouth!