Removed 2nd RAM stick to install windows 7, now computer won't boot with both installed

[ChristianMcDermott]

see above. I had 2x G skill 4gb ram sticks in my computer for about 2 years now. I recently had an issue that required a fresh install of windows 7. In order for the installer to not hang i had to take my 2nd RAM stick out. Now when I put both sticks in it won't boot, all lights and fans come on but monitor stays black, no beeps. I have tested both sticks in the 1st ram slot and the both work individually, but with both installed I get the aforementioned error. this is very troubling because the exact same setup as worked for 2 years prior to this and I can't surmise why it would suddenly decide not to.

my setup is:
biostar T-series motherboard
2x(ideally) Gskill ripjaws 4GB ram
2x radion 5770 crossfire
veretex 120GB SSD
AMD phenom 2 x4 955

 

[brispuss]

Faulty memory slot? Try DIMM's in different slots.

 

[digitaldoc]

If the RAM sticks work separately, than it is not a RAM issue. However, if you had to remove a stick of RAM to complete a Windows install, and now it will not run with the 2 sticks at once, this is a motherboard issue. Will need to RMA or upgrade the MB to get all the RAM working.