How to you enable it? I have a bios tar TA790GX 128M it has bios safety features built into it I will get a bios flash file before I do any thing just in case something goes wrong I can re flash the bios.
Since you have a Biostar board, you should only have to set ACC to 'auto' in the BIOS, then reboot.
I was able to unlock my 720 BE on my Biostar mATX board by doing this. Of course you might have to raise your voltage a little (1.45v) to stabilize things, but this is your best bet.
If this doesn't work, chances are you have a (truly) bum core.