GA-MA790GP-UD4H + Phenom 550 won't post

[Screenager]

Hi there. This is my current config:

MA790GP-UD4H
Athlon 64x2 5200+ (65nm brisbane)
2gb ddr2 800 A-Data
XFX HD4870
LC-Power Hyperion 700w

I wanted to upgrade my cpu, so i got a Phenom 550 (rev. c2)

After installation, it didn't post: no beep, no display, fans&hdd spinning.
So i took everything out from the case, unplugged everything, did a CMOS reset (left the battery our for an hour to be sure), and it still won't boot.
I did anything: only one stick of ram in each slot, integrated video card, various bios version (if i use my old 5200+ everything works fine), cmos resets, but nothing seems to work.
Weird fact: if i use phenom's box cooler, its fan will always spin. If I use my AC Freezer, fan will spin a little when i turn computer on, then stop, and spin a little again when i turn it off (I have to use the psu interruptor to do so).

Any suggestions?

[artdrivers]

Re: GA-MA790GP-UD4H + Phenom 550 won't post

It still is quite possible the CMOS still didn't clear. You may want to try unpugging the power chord first. connect the CMOS jumper pins for 20 seconds, or leave battery out overnight and take a wire and touch the negative to the possitive contacts on the motherboard for 20 seconds then reinstall everything.

So i took everything out from the case, unplugged everything, did a CMOS reset (left the battery our for an hour to be sure), and it still won't boot.

With this statement do you mean everything including the motherboard? As an out of case bench test?

http://forums.tweaktown.com/f69/how-perform-p-o-s-t-bench-test-38512/

I did anything: only one stick of ram in each slot, integrated video card, various bios version (if i use my old 5200+ everything works fine), cmos resets, but nothing seems to work.

Did you go into BIOS and be sure your onboard graphics are set to enabled before switching to onboard graphics? Try the old card and then go into BIOS and Load Optimized defaults. Then unplug power chord and remove GPU card and switch montor plug to the onboard again.
Other suggestions.
So it will P.O.S.T. and you can get into BIOS, but it won't boot into your OS? The original install is it in RAID or AHCI? If so you need to adjust settings in BIOS for this. Also in BIOS manually adjust settings for your memory. We are not aware of what OS you are using, but in most cases you need to perform a new install, or repair install when you change the CPU.
Let us know how that goes.

[Screenager]

Re: GA-MA790GP-UD4H + Phenom 550 won't post

I'm sorry, i meant - as stated in the title - that it doesn't post, not boot; so yeah, i can't even get in the bios. Yes, the motherboard, as suggested, was taken out of the case. I'm using Windows 7, but it's not revelant as it doesn't even post

[artdrivers]

Re: GA-MA790GP-UD4H + Phenom 550 won't post

I updated my first post with suggestions read it again.

[Screenager]

Re: GA-MA790GP-UD4H + Phenom 550 won't post

Yep, integrated card is enabled and works, if I use it with my old 5200+, it will post and boot fine. I'm starting to believe it's a faulty cpu, i'll try it on another rig or directly return it to the shop.