How to debug crashing system?

[you2]

built a system a couple of months ago and it has been rather unstable (getting worse). The components are:
--
nf4 ultra-d
fsp 600w-gln (over kill)
x1800xt 512mb
2 1gb G.skill D500 F1-4000USU2-2GBHZ
san diego 3700+
1 optical eide
1 74gb raptor
--
I am not overclocking - memory is using auto defaults (but look correct from atool/cpuz) and proc is at 2.2 ghz. Clearly something is bad (memory, cpu, psu, mother board).

Any suggestions of how to find/figure out what is busted? I do not have a probe so i cannot measure voltage directly but i am running mbm5 which seems to indicate reasonable values. Again according to mbm 5 max cpu temp is 45 with mean around 42. max video temp is 81 (which is normal for 1800xt) north bridge is 50c.

I just want to figure out which component is bad and fix it !

Thanks,
You

 

[sniperruff]

standard trouble-shooting procedures:

1) unplug everythnig from mother board. now plug in PSU, video card, 1 stick of ram and the HD and boot up
2) if crashes, then it has to be one of those components.
3) add the other pieces one at a time and repeat.

 

[you2]

Ok. Well not too much to try given that there is not much in the system. The painful part is that it doesnt' crash right away. Usually it takes an hour of prime95 (or a couple of hours of your favorite game). Once it begins to crash it than crashes more frequently until it has been unusued for a while.

This sort of suggests (to me) that it is heat related but nothing is getting that warm (with prim95 running the video card stays toasty cold) and cpu temp peaks at 46 (with prime95) and north bridge @ 50.

Bleh what a pain in the arse.