BIOS ROM Checksum Error?

EVERY time i boot my PC it shows it checking my GFX card (a 64mb card in this case-an old one for testing.) that goes, then this error appears, and it tries to find the A: Drive. I don't have a floppy drive..... I do have a USB drive though. Although it fails to detect it with (or even without) the BIOS repair diskette in it. I have tried resetting the CMOS with the on-board jumper, i have tried removing the 2032 battery next to the chip. i thought it may have been the RAM, i have two sticks of DDR2 533mHz 512mb RAM. I have tried the two sticks together, swapped round, one in one slot, the same in the other, all combinations, no luck. The PSU seems ok, no smell or discolouring of the molex cables. I have tried everyhing and now am stuck......
New MoBo??

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...i cannot access the BIOS, it isn't passing the POST.....
just beeps like mad.

Best Answer - Chosen by Voters

Once remove and again fix your GFX card in slot.
if problem continue remove permanently use VGA port for your monitor. If you dont have onboard VGA then use PCI VGA card or new GFX card. for other problem do this
Check battery charge it may be down ,
fixt it at proper place . start system go BIOS of CMOIS pressing F1 or Del key you will be inside BIOS setup .
Check all the option you will find Deskett A drive disable and one place you will get boot priority(normally in boot option)change first boot devices as hard disk press F10 to save change.
Restart
for last change your RAM then check