Need help with my P35 neo combo

I bought and installed new hardware to my computer motherboard, (MSI P35 Neo Combo) memory (Transcent AxeRam DDR2 800+ Dual Channel Kit) and power source (Nexus NX500, 500W).
Now im facing severe problems with my monitor and memories (Propably with motherboard too=). The problem is that i can insert only 1 memory module to slot. If I insert second, the monitor won't show any activity at all. I've tested all my computer parts before and everything seems to be working just fine. It just seems that there's only one memory module in the whole world that makes my computer work fine.
During start-up it shows error message whitch says: Last memory over clocking failed - or something like that.

Can you guys help me?

 

Then the memory that you got is DOA. The only way to fix it is to send it back for a replacement.

 

i tested with G-Skill ddr2 800 dual channel kit also.
Didn't work out

 

It'll be a faulty memory slot on the motherboard. That can happen sometimes.

 

Yea. Going to get it tested today. The thing that bothers me in this matter is why that one memory module can work on both slots but when i insert 2nd module in, my monitor won't show any action