Hardware Problem - Mainboard?

[@maniexx]

So, my computer decided to fuck up.
It was after messing with the OS (Windows 8 FTW) - So I assumed unplugging hard drive and booting up some live cd would help. It didn't - Some splash screens and consoles loaded up, but never the full grafical OS - and I tried a few. Then I went to test my RAM with memtest and found out it was broken - so I sent it to the manufacturer, got my return. I tried to boot it (a live cd) with new (tested) RAM and no hard drive - same failure as before. If I boot it up with the drive, it doesn't even boot - it stops after Veryfing DMI pool data. Also it quite often says CMOS failure (but not everytime) so I bought a new battery - and it still does.

So:
RAM - checked.
Hard drive - irrelevant.
I assume it's something with my mainboard(ABIT IN9) than. But I have no clue what could it be and how I can fix it. Any ideas? (I can post more info, just tell me what is necessary) Thanks in advance.

[Jorpho]

If the motherboard's dead, there's really not much you can do except get a new motherboard. If some of the capacitors are bulging or falling off, you can try replacing them, but it might not be worth the effort.

Other unlikely possibilities are that your power supply is going, or that something is overheating. In the latter case, you can probably find some kind of temperature monitor in the BIOS. Perhaps you have a badly-applied CPU cooler, or maybe your CPU cooler is unplugged. As I said, that seems a bit unlikely, though.

[@maniexx]

Could that be a BIOS problem? I mean - could updating BIOS fix it?

[Jorpho]

I doubt it. You can always try and find out – except if your system is freezing up that quickly after boot, the risk is that it will freeze up midway through the flashing process, and then you'll really be screwed.

I forgot to add that you should also try unplugging any expansion cards you might have in, try booting with only a single memory module installed, try it with the module in different slots, etc. and see if you can find some combination that works.