Hi guys,
I've got a desktop system, specced as follows:
Case: Antec 300, two Noctua 80mm fans in the front, plus the two standard fans top and rear (both set to "M" speed).
PSU: Corsair HX 620W
Mobo: ASUS P5N72-T Premium
CPU: Core Quad Q6600, SLACR. 2.4GHz standard, usually overclocked to 3GHz stable.
RAM: Four sticks Corsair TWINX XMS2/Dominator CM2X1024-8500C5D -- XMS2-8500, 1GB/stick (4GB total), 1066MHz, 5-5-5-15, 2.10V. Have also tried two sticks (for troubleshooting purposes).
HDDs: One Seagate 500GB, two WesternDigital RE2 500GB. All in "JBOD" mode, not RAIDing.
GPU: EVGA GeForce GTX260 standard edition (NOT overclocked), 896MB
Extras: Lite-On DVD rewriter (LH-20A1P if memory serves, it's on the ATA bus)
I can boot the machine fine first thing in the morning, and it'll stay running for about ten minutes. At that point, the screen freezes completely (no response to mouse/keyboard -- even Alt-SysRq-K does nothing). Hitting the front-panel RESET button makes the DVD drive reset (it does its little shriek-tick-tick warm-up dance) but the screen remains frozen.
The power switch does nothing -- I can hold it for ~5 seconds and the machine will shut down, but the Instant-off feature is DOA (that is, if you're in the BIOS or the bootloader you can press the power switch once and the machine shuts down immediately).
If I switch the machine off at the wall for a few minutes then try again, I can sometimes get the BIOS to appear -- it gets to "Main Processor: Intel Core 2 Q6600 2.4GHz" then freezes solid again. This has been getting steadily worse -- it used to get through the BIOS, reboot OK, then either freeze at the bootloader (GRUB) or carry on and work fine for the rest of the day. I should probably point out that once it's working, it'll work until it's next powered down. Then the whole sad dance begins again.
At no time during the reboot is there any HDD activity -- the HDD Act LED stays off. Sometimes when it crashes in Linux or XP the disc activity LED is stuck on.
I've already pulled out all the extraneous I/O cards and dropped back to 2GB RAM (one matched XMS2/Dominator pair) and I'm getting nowhere. Short of replacing the motherboard, CPU, RAM, GPU and PSU (at which point I might as well scrap the machine and start over), is there any other troubleshooting I can do?
I have a very limited budget (engineering student!) and would rather not buy a fairly expensive replacement part (motherboards and PSUs seem to sell for around £100 each) only to find that it's not the cause of the problem... :-/
Any ideas?
Thanks,
Phil.