Computer Randomly Freezes, then won't boot/post

[Cmd.Keen]

Hi Guys,

My computer started this strange behavior this weekend seemingly out of the blue. It will randomly freeze up on me. Everything looks fine on the screen but nothing will respond and I have to do a hard reboot by holding in the front button. When I power back up, nothing happens, the computer won't boot, no post, and my lcd displays a no input message. In order to get it to boot, I have to open up the case and reseat the ram in different slots.

Sometimes it freezes again during the boot, but usually it makes it into windows and lasts for awhile before booting. The last time it was several hours and froze sometime over night after I had gone to bed. A couple times it has just rebooted on me in the middle of usage and started back up on its own.

I'm really not sure what to do at this point. I've had some other issues with my machine that could point to the motherboard being an issue. I currently have 6GB of ram but can only run with 4GB OR 2GB or my computer has lock up issues when using all 6gb. The ram tested on its own is fine, but all together I get the same computer lock up and then no boot afterwards. So I have just been using 4gb of ram (2x2GB sticks) for the past month or so.

Computer Specs:
Intel Core 2 duo E6600
Asus P5B Motherboard with P965 chipset
OCZ 2GBx2 and 1GBx2 (using either or) PC2 6400
EVGA Geforce 8800GTS 640meg video card (also have a Geforce 8600 GT 512mb I can use for testing purposes)
Using SoundMax integrated audio at the moment
PSU is a 500watt Ultra Xfinity (ULT-XF500).

The processor I bought the week it was publicly available in the summer of '06 I think it was. I bought the motherboard at the same time and remember it was one of the very few available at the time that supported the new Core 2 duos. The psu was also bought at that time as was the 2x1GB of ram. The video card and 2x2GB sticks of ram I bought recently (1-2months ago) and have been running them since.

Any advice is appreciated. Thanks,
Jason

I assume since you've been removing/replacing ram that the inside of the case is clean, sometimes a heat issue will cause the problems you are having. I would make sure all the fans are spinning freely and clean of dust. I also would stick to just 2x2GB of ram, filling all the slots can make the system unstable. You might look at a bios update also.

[Cmd.Keen]

I'll blow all the fans out and check that everything is clear and clean. But in general it doesn't look too bad. And the bios I did update a month or so ago when I first tried add the new ram and got the lock up issue.

I've noticed another odd thing happening. At first I thought this was just coincidence, but now I'm not sure. Whenever I lift my case from laying down on its side to standing up (mid size tower case) it almost always freezes. I've noticed the case, and the motherboard, twist slightly when I lift it from the corner. Almost everytime I lift it, or shortly after lifting it, I get the freeze. So far it has not frozen while laying on its side, tho it has randomly rebooted on me once. This could all be coincidence or it could point to connection issues.

However, despite all this the first time it froze up, the only thing I was doing was changing the display connection from my lcd tv to my smaller lcd screen.

[not important]

I was going to suggest running MemTest after reading the first post but after reading your second I would suggest making certain your graphics card is fully seated and the connections are secure.

[glc]

If the motherboard is shifting, something is not right with the mounting. I'd pull everything out of the case and put it back in, paying close attention to your motherboard standoffs and screws and I/O shield.

This may or may not have anything to do with it, but Ultra power supplies are highly suspect.

Running memory diagnostics is NOT a bad idea.

[Cmd.Keen]

So I pulled everything out of my machine. Cleaned it all out, tightened the standoffs, and put it all back together making sure everything was nice and snug. So far its been running with no freezing. So if I'm lucky, it may have just been a loose connection.

That being said I've had several recommendations to replace the psu, as well as someone telling me a 500w psu is plenty for what I've got. So which is it? If 500w is fine, is it more of a quality issue. I realize my psu is just your average brand, so is it not as likely to hold up under heavy usage?

[not important]

500W may be plenty but quality is the concern.

[glc]

It's more of a quality issue. Ultras can be unstable. 500 watts is plenty for your setup.

This is a quality reasonably priced unit:

http://www.newegg.ca/Product/Product...82E16817104037