i tried to boot the machine withought the 2 cd-roms, but I will try what you recommended above later tonight (just cpu, one stick - that's what i have now, and video card).
What happened with my previous processor was this:
I was trying to clean up the whole motherboard, and around the processor area(i can't remeber exactly but I think I took off the heathsink and unscrewed the fan because they were pretty durty /i had a small accident/). After I started the machne, I could smell something bad, and in a few seconds the machine just shut down by itself. I thought it was the power supply at first, so I tried a different one, but it didn't work. I was able to run the pc for just a few seconds every time i pressed the start button and there was some strange noice, and the pc would automatically shut down again. Then, I removed the processor, and started it again, and the pc kept on running until I shut it down. That's why i said I think the processor was messed up. Now as I replaced with with a new one, it does not have that problem, but I cannot boot up for some reason?!?