Windows 7: Windows 7 wont boot after installing RAM

Hello,



I recently decided to add 4 more GB of ram to my system, but when the sticks are inserted windows wont boot. Currently I have 2 GB of this ram: Newegg.com - BUFFALO Firestix 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model FSX800D2C-K2G .My system has ran fine with this RAM.

When I add two more sticks of corsair 2MB to the system (two of these: Newegg.com - CORSAIR 2GB 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Desktop Memory Model VS2GB800D2 G) for a grand total of 6 GB, windows wont start. The four sticks are of the same speed (2 are buffalo and 2 are corsair).

More Information:
I've looked in the BIOS when all the sticks are inserted and the bios displays 6 GB of memory which is correct, yet no windows boot. I have tried inserting the new sticks into the slots of the old sticks, no go. I have tested the 2GB sticks individually and they work fine by themselves. Its when I add more than 2GB of ram I run into problems. I also tested every RAM slot and the computer boots just fine as long as only 1 2gb stick is inserted.


I have windows 7 64 bit
Here is the motherboard I have: Newegg.com - MSI P6N SLI Platinum LGA 775 NVIDIA nForce 650i SLI ATX Intel Motherboard

Any idea on what the problem could be?