OMG......don't tell me you flashed the BIOS and halted the update before it was fininished or flashed with the wrong BIOS? If not, then Jumper the Mobo to reset the BIOS or take out the CMOS barttery. If you still get a check sum error, after the BISO Reset to default, your mobo may have become a frisbee!!
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.