Hey guys. I've built about 20 or so systems in my day, and just finished putting together my first Core 2 Duo / SATA setup a few days ago.

The hardware specs are as follows:

• GIGABYTE GA-P35-DS3L LGA 775 Intel P35 ATX Intel Motherboard - Retail
• Western Digital Caviar SE WD1600AAJS 160GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
• Intel Core 2 Duo E4600 Allendale 2.4GHz LGA 775 65W Dual-Core Processor Model BX80557E4600 - Retail
• Microsoft Windows XP Home With SP2B 1 Pack - OEM
• APEX TU150 Black Steel ATX Mid Tower Computer Case ATX 12V 400W with 20+4 pin Intel/AMD listed Power Supply - Retail
• MSI RX1550-TD128EH Radeon X1550 Support up to 512MB (128MB onboard) 64-bit GDDR2 PCI Express x16 Video Card - Retail
• NEC Black 1.44MB 3.5" Internal Floppy Drive - OEM
• ASUS 20X DVD±R DVD Burner with LightScribe Black SATA Model DRW-2014L1T - Retail
• G.SKILL 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model F2-6400CL5D-2GBNQ - Retail

The installation went smoothly. No hiccups whatsoever. Driver installation went fine as well. In fact, for the entire 4-5 hours I was in possession of the box, I had no problems at all. System was working fine.

The next day, the guy I built the system for claimed it was freezing up all the time. Of course, I needed more information. He said once it happened while coming back from screensaver, once it happened right after a restart, once it happened right after opening Photoshop, and once after opening FireFox, minimizing it, and leaving it for a few minutes.

Thus, unfortunately, there appears to be no pattern. I obviously immediately thought hardware, but since I have no idea what would cause this (aside from replacing each and every component separately), I took a much harder look at the software he had installed. Photoshop, Firefox, and his Printer software (lexmark). That's about it.

So I went over that evening to get a closer look myself. When I arrived, the computer was in it's frozen state. The contents of his desktop, and mouse cursor were exactly where they were when the computer froze. I proceeded to restart the computer and immediately examined the logs. Again, nothing obvious in the logs.

I installed some benchmarking software, along with SpeedFan to see if any temps were out of whack (wasn't sure about my heatsink installation - those 'new' things are a little whacky). Ran speedfan while running the benchmarks, holding CPU usage between 50-100% for about 10 minutes. Temps are normal.

I updated the bios to the latest version, which appeared two be two versions behind. I also removed and re-installed ATI drivers. It also turned out I had inserted the dual-channel RAM incorrectly (again, it had been awhile ). I had put both sticks of RAM directly next to each other, in DIMM 1 and DIMM 2, rather than DIMM 1, and DIMM 3. Stupid mistake, but I didn't think it would be the root of my problem.

So after making those changes, I let the computer relax for a few hours, checking every 45-60 minutes or so. Didn't lock up once for me.

I began to think that my changes may have actually fixed the issue. The next morning, the owner mentioned he was not having the problem anymore. Not 10 minutes after that, he reported that the computer had locked up. It proceeded to lock up about 5-6 times during that day as well. Again, no obvious pattern.

So I picked up the computer and brought it to my house. I was beginning to think perhaps he had a short in one of his USB cables which might have surged the system. So I figured it'd be good to bring it somewhere else. For about an hour, I had no problems. Then it finally locked up. It had locked up after I had set the Screen Saver to 20 minutes (default XP) and power settings to turn monitor off after 30 mins. It locked up about 5 minutes after it went into Screen Saver.

At this point, I was beginning to think it was only happening while idle (despite what the owner had reported). So I did some googling, and found quite a few articles on XP locking up while idle. I performed several actions which were suggested for a variety of problems:

• SCRN SVR = unchecked 'on resume, display welcome screen'
• SCRN SVR > Power > Advcd = unchecked 'prompt for pw on return from standby
• Key to 0 (from 3): HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters EnablePrefetcher
• 'Enable' to N (from Y): HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Dfrg\BootOptimizeFunction
• Run Command > SERVICES.MSC > Rt click on "Indexing Services" > Properties > Startup type > Disable
• Run Command > sfc /scannow
• RUn Command > msconfig > diagnostic startup > reboot

All of the above changes had no affect on the issue. The system was consistently locking up after about 10-30 minutes of use even after the above changes.

Finally, I started the system in Safe Mode. I left the computer on from about 8am till about 5pm, and it did not lock up.

Up until this last part, I was almost 100% confident that it was hardware related. If so, however, it should have also happened in safe mode.

I'm running out of ideas. I'd love to hear some other perspectives.

If you made it this far, thanks!

Whats the brand of the PSU? Did it come with the case? The graphics card you picked is a piece o crap.

Run memtest on the memory and if you get know errors try a different PSU. And it dont hurt to double check the temps.

It could possibly be the graphic card drivers as well. Are they up to date? Try an older on if they are. Im pretty sure safemode uses default graphic drivers, someone correct me if I'm wrong.

The PSU is a pile. Whatever came with the case. Just checked - it's 'Allied'.

I'm also aware the Graphics card is whack. The prerogative for this build was 'the cheapest with the most (and highest) reviews on newegg'. The owner will do no gaming whatsoever, so this fit the bill.

Running Memtest as we speak - about 19% done right now with no errors. Will report back when finished.

The graphics card drivers were also garbage. When I mentioned I re-installed the gfx drivers, I really had uninstalled the drivers that were packed onto the CD w/ the card, and installed ATI Catalyst Ctrl center w/ new drivers. I believe the GFX chip is X1550.

Oy.

Okay - memtest 31% w/ no errors.

^Agreed with roadrunner . Imo, it is probably the PSU. Run Prime95 and other benchmark to test stability. If it is the PSU it will cause lock up while running Prime95. It could also be a driver issue or RAM. If it doesn't fail after about 10hrs of Prime95 try running AtiTool "Scan Artifact" and see what happens.

Shadow - awesome - thanks for those resources. I'm going to let memtest finish (69% - no errors) and I'll run Prime95 and report back.

Thanks, guys.

Your welcome. Hope we can help you get it worked out. I' going to go out on a limb a put a 90% its a PSU problem.

I hope you're right, a PSU swap would be welcomed. In fact, I was weary even before building it about the PSU - was not sure how the Core 2 Duo's rated as far as power consumption, as well as SATA drives.

My last install was about 2 years ago, and I had built a bunch of cloned computers for friends. Mainly P4's with regular ol' IDE HDD's.

How long should memtest run for? This is my first time using the software - not sure how many tests there are. Currently it's on Test #4, 28% Pass, 81% Test.

Atleast 2-4 hours. Maybe longer. Let it run all night and if it hasnt locked up by morning its almost has to be the psu unless it is a bad driver somewhere.

K - cool - sounds good. We'll see what happens.

Okay - memtest has been running for 12hrs and 17 minutes. 32 passes with no errors. Is it safe to say the memory isn't the culperit? Should I end the test, or continue?

After 12 hours it's completly safe to stop memtest and rule out bad memory, switch to orthos (or 2 instances of prime95) and start checking, I recommend the blend test to stress both the CPU and RAM at the same time

Awesome - is this what I'm looking for:

http://www.techpowerup.com/downloads/385/

Also - should I run this in Safe Mode to rule out any driver-related causes?

^Yes for both questions.