new computer not working right...

I just bought parts for a new system.

500W earthwatt antec PSU
Intel Q9450 processor
Gigabyte EP35-DS3P mother board

I don't have all my parts I want yet, but I wanted to see if those parts were working.
I am using RAM and a old video card from my bros computer. They came with his computer bought from HP, the RAM is DDR2 800 and the video card fits into my PCI-E slot, but I don't know the model. Its not high end stuff though for a motherboard made for gaming. could these parts be the reason why my new computer isn't working right?

I am using my old IDE harddrive with info on it (dual booting with ubuntu and XP using GRUB loader) and my old IDE dvd drive. I'm pretty sure I have everything connected correctly. except maybe the front panel stuff (Power SW, HDD LED, those things). they seem to work properly, no matter which way I plug them in (negative/positive), so I'm confused about that part...

so...whats happening on my computer right now is...the motherboard came in revision 2, which didn't support my processor, so I updated the BIOS successfully, and it shows up the new version in the POST screen, but its still not working right.

When I turn on the computer and get to the POST screen, it takes about 20 seconds to read the IDE cables for drives. It picks up the Hard drive, but not the DVD drive. After 40 seconds or so, if i dont press anything, it'll get to the "verifying DMI pooling..." screen, and after maybe another 40 seconds it tells me it failed to boot or something like "disk boot failed, but in disk and press enter". I'm not sure if it means my hard drive or the DVD drive.

could the new processor or motherboard be screwy? I feel like going out and buying a new set of RAM just to check it out, but I really don't want to reformat my hard drive...I dont think the hard drive is the reason why its like this though...I dont think it could cause the system to be running so slowly

on this motherboard?

the ram isn't listed on the memory compatibility list, so I'm not sure about that, but it works perfectly on my brothers computer, so i know its not faulty.

the video works perfectly on my bros computer too. I'm not sure what you mean if it works on another computer...I guess I can try his 8600gt later....i know thats compatible for sure...but i dont know if he would mind p=