Hi everyone.
I tried the instant help with one of the gigabyte customer service people, and their suggestion did not help at all, so I'm going to start a thread here.
To start off, I recently bought a used desktop machine from a friend that's about 4 years old. It has the EX58-UD3R Gigabyte motherboard, 16GB of RAM, the CoolerMaster V8 CPU cooling system, two Hydravision 4650 (?) video cards, and a CoolerMaster 650W power supply. A while ago I started having an issue with it shutting down randomly without warning when it was in use. It would restart automatically, and just shut down again, and it would continue this cycle until I would press the power button after the phase LEDs turned off after the POST. At the suggestion of a friend of mine, I unplugged the USB ports (connected to the front of the case--A CoolerMaster GLiTE 430) in case they had a short, and things seemed to work fine after that (for about a month). However, just today it started doing the same thing. I've reseated the RAM, checked for viruses, cleaned the fan in the V8, and disconnected any hardware that wasn't absolutely necessary, and it still continues to shut down during use. I've entered the BIOS and let it sit and it doesn't seem to do anything abnormal, and the core temperatures are fairly reasonable (~40C). I even tried booting from a Ubuntu Live disc to eliminate the possibility of an operating system issue, and it still turned off when I was trying to use it. Likewise, when I booted into safe mode (with networking and with command prompt), it would do the same. I checked the voltages on the PSU output and they were all good, though I haven't been able to hook them up to a scope yet to see if the output is clean or if there's noise.
I'm wondering if you might know what is wrong, and how to fix it? This has really begun to annoy me, and it's important that I get this machine back up and running the way it should be, as I have important work to do on it. Any thoughts or suggestions would be greatly appreciated!
Many thanks!
Matt L.
EDIT: I forgot to mention--
When the computer begins to POST, I hear a single, loud beep, which from my research means everything is ok. However, I also just noticed that sometimes, right before it shuts down, I can hear two extremely quiet long beeps. I'm not sure if this is an alarm of some sort or what, but I thought I should mention it, just in case.