How do I get in the BIOS of an ML310

[Dennis TBS]

I have an external USB storage drive plugged in and I cannot boot the server with it connected. I assume the BIOS is trying to boot to this drive first which it cannot and the machine gets stuck. When I unplug the drive, the machine boots fine. I would like to get in the BIOS to see if I can change the boot sequence but despite all my efforts, I cannot get in. I have hit every key on the board and I can't get in. Anyone know how to get in??? Bios Version D12.