I've purchased a new PSU (Chieftec APS-550C) and installed it into my computer. After that my computer refuses to boot up: it spins up all the fans and drives, stays in this state for ~10 seconds without any output from video port or buzzer and powers down, just to make another try in ~3 seconds. This happens for both new and old (Chieftec GPS-450AA-101 A) psu.
I suspect that i've damaged my motherboard somehow, however, all i've noticed during inspection are small scratches on lines to realtek chip, but they were made months ago and everything was working (i don't use ethernet at all). I can't smell anything like smoke and couldn't find any burnt places; touching 'bios settings' jumper with screwdriver and keys provided no effect, however, if i take out all RAM, buzzer does three long beeps before system goes to reboot. Poweron time changes and sometimes buzzer starts to beep again, but i couldn't determine if this is the same series of beeps (system goes to reboot faster). If any RAM plate is in place, beeps are produced. Can anybody confirm my motherboard is 99% likely to be dead or suggest some tests to find it out? Also, should i bring back this PSU to the store, or it is likely that it wasn't PSU fault?
Current setup: MSI PH61A-P35 (B3), i5-2500K, Radeon Sapphire HD4850 1gb, CoolerMaster Elite 372 case, 2x Corsair 4gb RAM plates (CMX8GX3M2A1600C9), Intel SSD 520 120gb, WD Caviar Black 1tb 1002FAEX, WD Caviar Green 2tb 20EARX, M-Audio Audiophile 2496 sound board, Asus PCE-N15 WiFi pci-e board.
Update: i've put this new PSU into my home server and it booted smoothly, i guess there's nothing bad with it.