Random Mystery Reboot - Help please!

[BellaTech]

Been researching, testing and generally going nuts for weeks now trying to figure this out. Fairly certain it's a hardware issue but can't figure out WHAT!?

System FYI:
HP Pavillion m1280n, XPMC -SP2 (bought off the shelf 2006)
P4 - 3.2GHz Maxtor 6B300 Diamondmax HD
Radeon X600 Video PCI-E
NIC - Gig-e <-- added aftermarket 1.5 years ago
RAM: 4 x 1024 DDR2 SDRAM PC2-4200 (swapped out 2 x 512's at the same time as adding Gig-e, purchased new)

Issue: About two months ago the computer just randomly started shutting itself off! Sometimes it teases me, monitor goes to black (no blue screen) but box is not powered off. Have to hard-reboot. Other times it goes immediately into a re-boot cycle and then eventually comes back up.

Things I've done (not necessarily in order stated):
1) backed off all unnecessary applications
2) tested to boot to safe mode (still blanks out at it's own leisure)
3) replaced the PSU - Antec Earthwatts 380 NEW!
4) pull and replaced the cmos battery (let it sit overnight before putting in a new one)
5) reseated the RAM, video and PCI cards
6) checked all capacitors on the MB -- no bubbling, seeping or apparent damage
7) cleared / cleaned all dust bunnies and excess dirt in box (canned air only)
8) checked my BIOS settings after cmos battery replacement
9) not a monitor issue (have KVM that feeds to server also)
10) not a UPS issue - feeds to same UPS that protects my server
11) Virus / Spam is current and have checked for Trojan's and any malware.
12) not a heat issue - box is running cool and quiet

Brought it up this morning after replacing cmos battery (thanks Murf for the great explanation on your garage site). Surfed around this forum, checked email, ran standard applications, controlled reboot to safe mode, checked BIOS again and controlled reboot back to Windows.

It was just humming along fine. But then I had to get some work done and I've watching it from the other side of the desk. About 3 hours later, random blank screen. Had to hard-reboot again. All critical data resides on my server but it's really ANNOYING because I don't dare work on this computer for normal processing. I never know when it's going to bail on me! It's not used for gaming, only financial applications and standard MS Office stuff. The hardest push it makes is when I have my VWare running at the same time as some of the financial software. Haven't loaded ANY new software or updated drivers for at LEAST a year! (Sorry if I sound like I'm whining but I'm starting to get tired of trouble-shooting this problem.)

One anomaly I noticed when checking the BIOS:
BIOS settings read the RAM as PC2-4200 4096MB then gives a breakdown per slot. When I populate the "My Computer" info it says I have 3.12GB of RAM. Have downloaded the memtest but haven't had time yet to run it. Could this be creating my problems?

Anyone..... thoughts..... ?? Please?

[renegade600]

something to try if you are not running a 64 bit operating system. Take out 2 gigs of ram and run normally and see what happens.

[BellaTech]

Originally Posted by renegade600

Take out 2 gigs of ram

Renegade:
Thanks for posting a response. Tried this, box ran all night. Thus far, the most stable it's been.

So, pulling the RAM, what does that tell us? Does this mean the max RAM I can have in this box is only 2GB? The 4GB upgrade ran for over a year with no difficulties. What changed? <-- Rhetorical

DIMMs are labeled 1A, 1B, 2A, 2B. Need to add RAM in pairs, right?

[renegade600]

Originally Posted by BellaTech

Renegade:
Thanks for posting a response. Tried this, box ran all night. Thus far, the most stable it's been.

So, pulling the RAM, what does that tell us? Does this mean the max RAM I can have in this box is only 2GB? The 4GB upgrade ran for over a year with no difficulties. What changed? <-- Rhetorical

DIMMs are labeled 1A, 1B, 2A, 2B. Need to add RAM in pairs, right?

As far as why it worked before, maybe the ram went bad. Try the pair you took out and see if the computer is still stable. If not, then it could be bad ram.

sounds like your computer needs pairs but will not swear on it. Could not find info about it.

[Murf]

Does not require matching pairs. I think Dan hit it, one of those sticks is bad.

Now having XP Medium Center it will not recognize all 4GB, but will run fine, as it ran fine before.

[BellaTech]

Originally Posted by renegade600

sounds like your computer needs pairs but will not swear on it.

Well, apparently, it doesn't need pairs. Ran tests using 1GB only in DIMM 1A. Then 3 sticks ( 1GB each-Patriot Signature DDR2-533MHz) in DIMMs 1A, 1B, 2A. Reads all just fine. Added 4th stick to DIMM 2B, system wouldn't boot (could have been a seating problem). Swapped stick that was in DIMM 1A for stick in 2B. System came up fine but populates in CP properties at 3.12GB (sysdm.cpl). However, when I check the system information (winmsd.exe) the summary tells me I have total physical memory @ 4096MB. I'm going with the system information!

Next test: see if the box will run without interruption on 3GB of RAM.

If it does, what does this tell me? I have a bad DIMM on the MB? The RAM is all reading fine, regardless of what DIMM I use.

[BellaTech]

Originally Posted by Murf

XP Medium Center

It was a knee-jerk purchase. We needed something fast at the time. Tax deadlines don't wait! Been "making it work" but not my first preference in O/S, no question.

Not confident yet that it will keep running consistently w/4GB. Apparently that's been my problem but still don't understand why it's manifesting itself after over a year!

[renegade600]

Originally Posted by BellaTech

Well, apparently, it doesn't need pairs. .

finally found the info about your ram, your computer will run single but it really needs pairs to give the best optimal performance.

http://www.crucial.com/upgrade/compa...280n/list.html

[BellaTech]

Cool! Thanks Dan for checking on that. Presumed it but wasn't sure. Box is running, 2-hours and counting, on 4GB RAM (because Murf said it should). If it makes it past the 5-hour mark I'll be surprised AND happy!

Nice link! Bookmarked for future use! Thanks!

[BellaTech]

Update:
The box ran all day, normal processing. Seems to have stabilized.

All that work for a RAM shuffle.... go figure.

Thanks Dan & Murf for your help on this!

[BellaTech]

Update:
After a couple of days running this box OPEN, it appeared to have stabilized (ran for two days straight with no problems). Yesterday I closed it up and put it back in place on a rolling CPU stand under the desk.

It booted back up fine but after about an hour it went to black and I had to hard reboot again. Shut it down for the day and tried it again this morning. Took about 20 minutes and then it bailed.

Is this a heat issue? Box seems to run cool when it's open. Video card has a fan on it. Need feedback on whether replacing the video card or shuffling PCI cards around might be the fix.

Not certain it's about heat but what else am I missing?