Something bad happened to my PC several days ago. I wasn't near my PC, so I have no idea about what happened it was just halted. When I tried to boot it was entering infinite loops of a few seconds power up (cpu, hdds, etc) and then power down. I've tried to boot the system with no additional components (that includes hdd, video, network adapters and even memory) connected and that didn't solved the problem, so I've made a decision that most likely it's either some a problem with power unit or with motherboard. I've tried to replace my power unit by another one (which was expected to be working) and the problem didn't resolved again.

I've bought a new MB (ASUS P5KPL-AM SE) and tried to get it running with my old CPU and memory (I hope it's still alive). Since this MB include on-board video I've tried to run the PC without installation of mine video. The PC wasn't running and the BIOS was beeping one long signal following by two short (Does it means a video problem?). After that I've installed my video adapter to PCI-E slot and tried to boot the system again and the BIOS was beeping the same. I don't get it. I may expect some problem with CPU and/or memory since I don't know what happened to my PC (maybe some power failure or something different), but not with video and not with on-board video on newly bought MB. How can I understand what's wrong with my system now?