Maximum PC

I have a new (older model MOBO to work with old parts AM2 CPU Etc.) It is a Biostar TForce 590 SLI Deluxe. This was to replace a defective Gigabyte GA M59SLI S5. The thread on the previous problem is here.viewtopic.php?f=36&t=112961
Anyhow after a long delay I am finally trying to get the rig running. Problem! I get no video output or keyboard power to the illuminated Logitech keyboard, and as I mentioned earlier no video output to show a POST screen on the display. I swapped DVI cable with a new one to make sure it was good. No change. I tried the monitor on another PC. Monitor is good and worked on the other PC. Now the original Video card is a Saphire HD 4870. Believing it was bad I purchased another card. A XFX 6870. Hooked it up, still no video output or display . . I then hooked up a back up card, a EVGA GE force 7800 GT CO 256 MB. I have a post screen on the monitor and a keyboard with power. Is it possible that the Biostar MOBO does not " Play Well " with Radeon cards? I have yet to install any drivers or a BIOS update, this may cure the problem but with my 2 Radeon cards, no display output. Any help please.

Have you tried running the rig with only one stick of RAM in it? Those Biostar motherboards were known to not send a video signal to the monitor if one of the sticks was defective.

No I did not, it did work with the old EVGA 7800 series card. I got around to calling Biostar tech support. Biostar said that because the MOBO is older,with the nForce 590sli chipset, it will only work with card up the the Ge force 7900 series and the Radeon cards up to the 1900 series,or PCI Express X16. The Biostar board supports PCI express X16. My newer cards, the 4870 and XFX 6870 require PCI express2.0 X16. This is what the tech explained. I am gonna have to shell out more cash , to get a AM3 board MOBO and RAM CPU Etc. order is placed wit New Egg as we speak. Hard lesson learned , I was trying to revamp a dying machine and now spending more cash. Live and learn. I will save the old AM2 rig and throw something together for my sons they can use for a while and start fresh with the new parts including the XFX 6870 card.
thanks for the response.

I know for sure that the logitech illuminated keyboard does not "play nice" with a Biostar MB. I had the same problem, the computer would hang at the "USB controllers" part of the startup if plugged into the MB usb port. I solved this by plugging the KB into a pci usb controller card and it loads fine, but not until after you get past the part to enter bios. I had to use a cheap generic KB to enter the bios screen. Lots of complaints if you google this. Sorry, can't help on the video card situaton. Maybe related? Try another KB first. This should allow you to get to the post screen.

I was able to get key board power with the old video card PCIE X 16. that's the main clue. The newer cards were PCIE 2.1X16. This MOBO does not support PCIE X16. I should have researched this before I spent the cash for the new MOBO.
Moral of my sad story, not all "PCIE are created equal. "
I was in such a rush to find a socket AM 2 board to use my old CPU I rushed and got the Biostar.
I just started over with the AM3 Asus M5A99X EVO new CPU and RAM. Good thing New Egg is in driving distance for will call and "Fried" Electronics is close by too.
Thanks for your replies