Need Help computer randomly reboots

psycowars

Honorable
Dec 9, 2013
1
0
10,510
My mobo went out about 6 months ago got new mobo, cpu and memory (computer was 5 years old so had to change all 3)

Worked fine first couple of months, but for past say 2 maybe 3 months I suffer random reboots.

Reboots seem to have no commonality, I have run my computer without issue for 12+ hours without issue, and then there have also been times where just starting it will cause a reboot up to 3 times just trying to load windows. Issue has happened even while sitting in bios simply looking at the settings, not making any changes.

Bios has been set to default configuration.

No BSOD errors.
no noted hardware conflicts in windows.
no errors in event viewer.
memtest showed no errors on RAM.
chkdisk found no errors on any of my drives. malwarebytes and avg show no malware or viruses.
CPU Temp: under normal operation running 30c on core 0 and 38c on core1

Note: I have set windows settings to NOT "automatically restart" on system failure under the startup and recovery.

Few things to note: reboot most often occurs when taking some sort of action on the computer (though not always, as in the case of the bios reboots or on the times it was "loading windows"). This "action" can be anything from clicking an article link on a website like foxnews, viewing a video on youtube, or launching a program.

Current configuration:
Windows XP pro sp3 all updated.
mobo: Asus P8B75-M/CSM, 6 mo old.
CPU: Intel CORE i3-3220, 6 mo old.
RAM: Patriot single stick 4gb PC3-12800 1600MHz, 6 mo old.
Power: Allied 500 watt supply almost 10 years old.
HDD: All Serial ATA's. Boot drive: Western Digital Raptor 10,000 rpm (first generation also almost 10 years old), other storage drives are a WD 250 standard drive, about 8 years old, and a Seagate 250 yanked out of a damaged laptop, about 4 years old.

Using on mobo cpu based integrated graphics and sound, (I know what your thinking, and if I could afford it I would get the 2 separate cards to help with memory and cpu load, but I've been unemployed and/or underemployed for almost a year and just cant afford it)

Also I should note that about 95% of the time these reboots happen it is preceded by a sound change in my computer. The "sound" is a pitch change from high to low almost like something like a fan or HHD is "spinning down","slowing" but I run my computer with an open case and visually don't see any change on the CPU fan at the time it happens.

Any Ideas what to try next are helpful.

Thanks

M.W