First of all, the bios you're using is a beta version so it could be the culprit. Unless you tried overclocking with older bios versions with the same result?
Other than that, after looking around some it'd seem that this issue is most often caused by power issues somewhere or mistakes when overclocking.
One of the easier things to check would be unplugging the PC and resetting CMOS or, if that won't work, take out the CMOS battery for a minute or so.
Maybe try upping the voltage a little on FSB, NB and CPU, lower your RAM multiplier by 1 and try raising FSB frequency by 1. Leave everything else stock. If it won't work then, most likely, we can rule out overclocking being done wrong.
Just in case, please let us know what is your PSU?