What would make a PC constantly reboot itself while loading windows?

LiekOMG

Golden Member
Jul 5, 2000
1,362
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My friends computer is acting up. Its a custom built thing that I scrapped together for them from some old parts. Its running an AthlonXP.

The problem is that while windows is loading, it will just randomly reboot itself. It usually takes a good 1-4 reboots before I can finally get to the desktop. Once IN windows, it never reboots, however. I've formatted the system and it continues to do it, so its not a software issue. Also, the computer doesn't always POST right away. As in, i'll turn it on, the fans will spin, but nothing appears on the screen for a good 1-2 minutes, and THEN i'll hear the POST beep and the bios screen appears.

Is this a sign of a faulty PSU, or a faulty motherboard? I've noticed a few of the caps are a bit leaking, but they've been like that for years and never given me an issue (it was my old computer).
 

msparish

Senior member
Aug 27, 2003
655
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I had the issue with the computer rebooting until it got into windows. It was the PSU.
 

willtriv

Member
Oct 21, 2005
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qft? (some one pm me with what that means)

I can't imagine this really being PSU but if you've got an extra one similar lying around to test it, its a quick check.
With me I often have this problem when memory is causing errors. My comp does the whole no boot into windows thing about once a day for windows. It never seems to do it with linux, but when i clock my ram a little slower it always works perfect. I'd rather trade off the one bad boot a day than 10mhz of ram speed, but your issue may be in a ram clock timing. Lookup the vendor ram timing and see if the ram timing in the bios is set correctly. I've had ram that ran for 7 month @ 2.5T that was designed for 3T (Cas) and then one day it just would reboot after posting constantly. I just scaled back ram timing and it worked fine again.

I hope this helps and if you would like to insult my insights you can PM me and save me the public humiliation.
:)
 

LiekOMG

Golden Member
Jul 5, 2000
1,362
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Originally posted by: willtriv
qft? (some one pm me with what that means)

I can't imagine this really being PSU but if you've got an extra one similar lying around to test it, its a quick check.
With me I often have this problem when memory is causing errors. My comp does the whole no boot into windows thing about once a day for windows. It never seems to do it with linux, but when i clock my ram a little slower it always works perfect. I'd rather trade off the one bad boot a day than 10mhz of ram speed, but your issue may be in a ram clock timing. Lookup the vendor ram timing and see if the ram timing in the bios is set correctly. I've had ram that ran for 7 month @ 2.5T that was designed for 3T (Cas) and then one day it just would reboot after posting constantly. I just scaled back ram timing and it worked fine again.

I hope this helps and if you would like to insult my insights you can PM me and save me the public humiliation.
:)

QFT = quoted for truth

Anyway, I don't believe its the RAM as the computer only started doing this recently and I never added new ram. It can also run prime95 and games stable for hours on end once in windows. However booting windows, and even POSTing is whats giving me trouble. I will try another PSU to see if that makes a difference.
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Check the capacitors on the motherboard. I will wager Aquaman's left nut that at least one will have a bulging top and may be leaking some. In that case it's only a matter of time before it blows.

Solution: new mobo.
 

OOBradm

Golden Member
May 21, 2001
1,730
1
76
check memory, and I had a problem very similar to that it would take me sometimes 5-7 tries to get the comp to boot but once it got into windows it was fine. It ended up being my mobo, I never found out what exactly the problem was but it must have been a shorted circuit or something somewhere. I'd just start swapping parts.