Computer will not boot with two identical ram sticks

[dandandawildmans]

Hello,
i recently purchased two patriot memory sticks and installed them in my desktop. they are DDR2, 1066, 4gb. They worked fine for 2-3 months then I took the computer to a repair shop because I was having problems with usb connected devices not working properly. they replaced the power supply (not sure why). when I picked the computer up, they told me one of the memory sticks was not working and they had removed it. I immediately had same issues with the usb devices so I ordered a new usb card and installed it myself. That problem is now fixed, however, I swapped out the memory stick they had left in for the one they said was bad and it worked just fine. Here is my problem: both memory sticks work in either of the DDR 2 slots as long as only one is installed. If both sticks are installed, computer powers on but does not boot up. Nothing on the monitor, no error messages, no blue screen, nothing.

 

[o1die]

Could have a bad ram slot on the board. Hard to place cause of the problem on the shop, but you should have pushed back and not accepted the system as it was. It will be harder now. You can rma the ram and if that doesn't work replace the board yourself instead of paying someone else. It's a good time to learn how to change out a motherboard. Newegg has open box boards fairly cheap (with no accessories and no backplate). You can use an esd strap to be safe, which prevents static discharge damage to circuitry (they can cost as little as $1). http://www.wonderhowto.com/how-to-install-motherboard-properly-143888/