If this is indeed the case:
1. Donor CPU - Sempron 140 or Sempron 145 ; cheapest supported CPU with lowest BIOS version.
2. Send MOBO to ASUS and they'll update the BIOS ; 2+ weeks
3. Borrow non-FX AMD CPU or go to a Computer Shop.
Hi i tried my Phenom11x2 Phenom BE but it was set at 4 cores so is seen as a B40 it did not work on the motherboard,
still get a quick flash of the boot up page prior to the monitor going black. I should have maybe tried it reverted back to 2 core. this is a real chicken and egg scenario.
First you need to reset the BIOS to defaults and then use the PII X 2. You can't set the processor itself to being 4 core unlocked permanently. It's the Mobo which does it.
So basically you need to reset the BIOS to defaults, remove CMOS battery, short jumpers, hit a switch whatever and then try to use the processor. Just boot into the BIOS after that. Don't try to change anything there, update to the latest BIOS and that's it.... your FX6100 should be good to go in that board.