Cold boot problems

Hi

2 weeks ago my PSU (a Cooler Master Silent Pro M 700W) crashed my pc.
I immediately contacted Cooler Master about the problem and received a new PSU, a Cooler Master Silent Pro M2 720W.

After installation I noticed that my PC wouldn't boot when it is cold booting. If I however let the PC run for about 5 minutes before restarting it boots fine.

My PC starts but doesn't go to the post when cold booted. It stops right at the moment when it should memtest my installed RAM.
The PC is not overclocked.

My 8X PCI-express slot broke about a year ago but after that my PC still worked fine (with the old PSU).

What I have done so far is the following:
- All the cables are connected correctly and all the computer components are correctly placed and reseated.
- Remove and reset the CMOS
- Switch RAM and/or placing only 1 or more of them in a slot.
- Remove all USB devices and checked each one if it conflicts with POST procedure.
- Double checked the PSU cables that need to be inserted into the motherboard.
- Flashed newer Bios and older Bios versions (via recommended Q-flash method)

My Pc specs are the following:
Gigabyte GA-MA790X-UD4 Rev 1.0
Amd Phenom X4 II 940BE
Ati Radeon HD5830
4 x ram = Geil DDR2-800 2Gb

When looking in the Bios setup I noticed that my PSU gives the right amount of Volts where needed.


I don't know what to do now. My PC is more than 2 years old so parts cannot be sent back for RMA.


I hope you guys can help me out.
Thanks in advance!

Kind Regards
~zanza54