How old is the system? Power supplies lose capacity with age so an older PSU that was running near its capacity to begin with may now be over stressed. List your full system specs if you can including PSU make and model if you know them or can find them.
Do you happen to have another PSU that you could test with to see if it occurs even with a known good PSU? I wouldnt use a suspectly problematic PSU in a good system though to test it out as that risks the good system.
The PSU should be at most warm, certainly not HOT.
Prior to your "recent" November 8 purchase the PSU should have had no problem running this system. Have you cleaned out the dirt/dust lately? I would make sure the case has good airflow with clean heat sinks and fans before I replaced the power supply. If you are overclocking, go back to stock speeds and see what happens. If it still runs hot after this then it's time for more and newer power.
This is a homemade system.. Most of the system parts are about three years old, power supply included.
I don't really have another PS to try.
I did recently buy a new video card, but this problem happened before I upgraded.
System as bought on 10/16/2006 7:26:10 PM:
2 Western Digital Caviar SE16 WD3200KS 320GB 7200 RPM SATA 3.0Gb/s 3.5" Hard Drive -Bare Drive
1 SAPPHIRE 100168L Radeon X1900XT 256MB 256-bit GDDR3 PCI Express x16 VIVO Video Card - Retail
1 CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model TWIN2X2048-6400 - Retail
1 Intel Core 2 Duo E6600 Conroe 2.4GHz LGA 775 65W Dual-Core Processor Model BX80557E6600 - Retail
1 ASUS P5W DH DELUXE/WIFI-AP LGA 775 Intel 975X ATX Intel Motherboard - Retai
1 MSI MX4000-T64 GeForce MX4000 64MB 32-bit DDR AGP 2X/4X Video Card - Retail
1 SILVERSTONE ST60F 600W ATX12V / EPS12V SLI Ready CrossFire Certified 80 PLUS BRONZE Certified Modular Active PFC Power Supply - Retail
Recently bought on 11/8/2009 7:23:11 PM:
1 XFX HD-487A-ZWFC Radeon HD 4870 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card - Retail
I have to agree with the above poster that this sounds like it could be a heat related issue. Just had a similar problem with my build. Try taking the side off the case and directing a fan to blow on the case. Then see if you have the same problems. If not, its likely a heat issue. I have to manually up the fan speed on my gtx280 in order for everything to run cool in the case.
is it possible that the fan on the power supply is failing?
would it help if i bought more computer case fans?
i thought about buying a 10 dollar walmart fan and mounting it back there by the power supply to see if that would work, but i'd rather not resort to rigging a fan to the exterior of the case
Yes it's possible that the psu fan is failing. No, more fans won't help a bad psu fan problem. You should feel the airflow coming out the back of the psu. If you can't and it's HOT to the touch then you need to replace the fan, not jerry-rig another one behind the case.
The OP listed 3 video cards... an ATI 1900, an old AGP card and then a 4870. If you have two (or more) cards in the system at once, definitely consider pulling one... and set your CPU/GPU to stock clocks. This ain't the time for overclocking. Also, verify that nothing is obstructing the PSUs overflow... most PSUs intake from the bottom and exhaust air out the back.