Just Some clarification:

Vista has been on since March
I'm not Sure if it overheats, but the power box is extremely hot and smells like smoke. The power light remains on but everything else stops, hd, fan, cd/dvd drive, audio, etc.

Thanks in advance
-TCL

Sounds like your power supply is faulty. Any OS should have minimal impact on heat produced or workload to produce that much heat. Many off-the-shelf purchased PC's are built to tight specifications and tolerances and this could be the case with your power supply. Try replacing it with a more powerful unit.

Also, check to see if you have not blown (or partially blown) the power outputs that are available on your motherboard. This can happen if you replace something as simple as a CPU cooler with a larger cooling capacity fan. The extra power drain destroys motherboard power outputs and you never know until it is too late.

Sounds like your power supply is faulty. Any OS should have minimal impact on heat produced or workload to produce that much heat. Many off-the-shelf purchased PC's are built to tight specifications and tolerances and this could be the case with your power supply. Try replacing it with a more powerful unit.

Also, check to see if you have not blown (or partially blown) the power outputs that are available on your motherboard. This can happen if you replace something as simple as a CPU cooler with a larger cooling capacity fan. The extra power drain destroys motherboard power outputs and you never know until it is too late.

It was the power supply

I have had a VERY similar problem. I have already replaced the power supply, with a higher power version. I still have the same problem. Prior to the problem occurring, I too had been running the system non-stop for a few months.
I sounds like my next step will be to replace the motherboard.
Is there anything I should watch out for in replacing it?
Are HP systems "picky" regarding compatability of the reset of the system?
What about reconfiguring the OS (Vista Home Premium) to work with a different motherboard? ( I am *not* well versed with Vista)

Thanks in advance for any helpfull responses or comments.

-JPFitz