Random restart/freeze even in bios

[strider2007]

hi guys,
my pc config is intel 865GBF mobo ,p4 3.0E GHz , (2*512MB) ddr266 RAM
visiontek xtasy ati 9600 256MB agp card,
seagate 160GB HDD,a CD Rom drive and an DVD Writer
300W psu| winXP pro SP2
since the last 30-45 days my pc is randomly restarting /freezing and some times just the monitor goes black with the cpu still on ,then numlock led responds for the first 3-4 strokes after that it stops responding .i just have to restart it to make in work.initially i thought it to be some virus or driver problems.but to my surprise it would some times restart or freeze even in the bios some times during memory check ,some times when we enter the bios setup.all this occurs very randomly most of the time it works fine but we just cant say when its going to happen could anybody sort out this for me

 

[DonNagual]

Sounds to me like your PSU is getting aged. It could also be your CPU or your motherboard, but I prefer to start with the cheaper parts first.

How many passes in memtest are you able to pass before you shut down?
From what you describe, it doesn't sound like an overheating problem, but might as well rule that out to be certain. Download and install this, and see what kind of temps your CPU is at:
https://www.techspot.com/downloads/547-speedfan.html

 

[strider2007]

hi,
the memory check i was refering to was the mobo's default memory counting sequence.i did also run the memtest, its records an error at some 55Mb position in the second test but that too in random its misses its sometimes and shows no errors.one thing i noticed is that it never shows any error if i check each of my RAM sticks one at a time. i do have have a lot of monitoring app's like mother board monitor and speed fan all show normal temperatures around 50-55 for cpu and 40-45 for Hdd .i read some where that for ps's of this type of config's we need an psu with minmum of 16AMPs on the 12v rails mine is rated as just 15amp's could that be the problem ?