MSI P31 NEO - Problem with memory upgrade

I've a MSI P31 NEO mainboard. Until now it gave no problems, but when i upgrated from 2GB memory to 4GB... it doesn't load Windows.
I've 4x1GB, 667MHz sticks.
My system is:

OS: Windows 7 Ultimate 64Bits SP1 - http://windows.microsoft.com/pt-PT/w...mpare?T1=tab09
Mainboard: MSI P31 NEO - http://www.msi.com/product/mb/P31-Neo.html#Spec
Chipset: Intel P31 - http://www.intel.com/products/deskto...1-overview.htm
CPU: Intel Core2 Duo E6300 1.86 Ghz - http://ark.intel.com/products/27248/...066-MHz-FSB%29
Memory: 4x1GB DDR2 667 MHz (2x OEM + 2x Kingstone)
HDD: Samsung 300GB SATA I/WD 1TB/WD 500GB/WD 1TB
Video: ATI Radeon HD 5450 - http://www.amd.com/br/products/deskt...-overview.aspx
Sound: Realtek High Definition Audio Codecs - http://www.realtek.com/downloads/dow...Audio%20Codecs
Optical: LG GSA-H20L - http://www.videohelp.com/dvdwriters/lg-gsa-h20l/1561
Cooling: Artic Cooling Freezer 7 PRO REV.2 - http://hi-techreviews.com/index.php/...er-7-pro-rev-2
Powersupply: LPJ12 500 TC Silent - OEM


I've already trieded with two sticks only, 2GB... and it starts fine. All the memory sticks work fine... in pair. All four, nothing.

P.S.

I've noticed that two of the memory sticks are single sided and the other two are dual sided! Could this be the origin fo the problem?

Does the OEM & Kinston ram have the same speed's and same timing's ? Pull either the oem or Kinston ram out and run CPU-z and look at Memory tab and write it down on a piece of paper. Do it with either both sticks of the oem ram and also click on the SPD tab. That is what the timings are for that set of ram. Compare it to the Memory tab and see if they both match. If not change the settings in the bios to match the correct timings from CPU-z SPD tab. Now put the Kingston ram in and re-run CPU-z and repeat everything once again. If the OEM & Kingston ram's timing's are different from each other, I'd ditch the oem ram and get another matching set of the Kingston ram.

From the P31 Neo User Manual.

Please note that the only time two Dual Sided memory modules are used, the other slots are vacant. In order to populate all four slots, single sided memory modules are required.

Yep!
I must buy another set of two SS memory sticks. Same as i've got from Kingston.
Thanks!

That kinda sounds like what I was thinking. One ram kit, seemed different from the other.

Well... i didn't know about the SS vs DS question. I bought a kit with the same capacity (2x1GB) and the same velocity (667MHz).
Damn the rest...

It's a shame that boards slots only support 1.0gb. sticks. I've got 8.0GBs. of Crucial Ballistix DDR2 800 laying around.

For what it's worth, on the same channels you should always have matched RAM sets from the same manufacturer, same series, etc.

Mixing different brands and timings of RAM will cause problems.