Need help installing ram

[jca2200]

Hi, I have a dell xps 700 series pc, intel core 2 extreme x6800 2.93ghz processor, came with xp installed and 4gig ddr2 667 ram. I recently installed windows 7 64bit and upgraded the ram. I went to the dell website and purchased 8gig (4x2) ddr2 800mhz, which is what their website said would be compatible with my system. However, since installing the ram the pc randomly powers down or reboots. No error messages or bluescreens. I reseated the memory modules, ran the windows memory test and memtest 86 and they're does not seem to be problem with the memory. I have the latest Bios and chipset for this mb. When I replaced the old ram the problem resolved. Why would this happen? Am I supposed to do something else after I install the new ram?
Thanks

 

[jaquith]

Clearly what Dell sold isn't compatible, send them back. According to 'Crucial' 1GB per slot is the max 4X1GB.

Buy these -> http://www.crucial.com/store/listparts.aspx?model=XPS%20700

 

[jca2200]

That's what I thought. Too bad. Customer service just isn't what it used to be.

 

[jaquith]

I edited above see the 4X1GB...

 

[jca2200]

I understand, but the dell specs for my mb clearly state that it should be able to handle the 8gig upgrade. However, facts are facts. So I swapped out the new memory and replaced it with the old memory which I never had a problem with. Guess what!!
The pc still powers down randomly. The PSU is a 1000w 3months old and you guessed it, purchased directly from Dell to replace the last psu which failed.

 

[jaquith]

1000W seems crazy high unless you have 2 ATI 5900 and crazy OC CPU + GPUs. Use Corsair and configure using this -> http://www.corsair.com/psufinder/default.aspx