this is a frankenstain computer that I've build for my mother that like to play old gdr.

• i3 3220
• mobo: MSI PH61-P33 (B3)
• 2x2gb kingston hyperX
• 1 hdd sata maxtor
• GPU Asus HD 7770
• Vultek PSU 600W (new)

When I power on the pc I have a black screen, no beep, nothing. the pc simply won't boot. BUT, when I clear the CMOS everything works.

The first strange thing is that the pc won't power smootly. I try to explain better: when I reboot the pc first shutdown power (all fan stop, all led down, like it's power off) then suddendly start, and It's really strange 'cause I've never seen a PC that reboot in this way, in a normal reboot, pc doesn't power off completely.

• So, I first try to play with BIOS, xmp, voltage on ram, ide/ahci, overclock, optimal setting, default setting. then I bought a new battery.
• I bought a new PSU
• then I take of the CPU and clean a bit of dust that I've found under the socket but didn't help.
• I try to disconnect all addictional fan of the case.
• I try to have only the power button connect and nothing else
• Then I take off 1 ram, and the pc starts!

now: I have two slot I try every single combination between ram and slot and I found out that both ram works, BUT if I insert two ram, pc won't start (until i clear cmos), If I insert one ram (eather in slot 1 or 2) the pc starts.

can be the mobo faulty? or I'm forgetting somthing? something I could try to have the two ram slot working? is an hw problem? a bios problem? I really want to give my mother this pc as gift but I don't have money now to buy an old lga 775 mobo. Thanks all for the advice and sorry for my bad english