Why did the update fail in the first place?
1) Are you certain you specified the bios for your exact motherboard and revision?
2) It sometimes takes longer than you think. Be patient, wait to be certain the process is complete.
I think it is safer to update the bios using the EZ Flash utility.
Download the bios to a usb drive.
To recover from a failed flash, read you manual, the section on the crashfree bios 3 utility.
If you can't even get into the bios, try clearing the cmos to entirely reset to the default original bios.
Here's how: http://pcsupport.about.com/od/fixtheproblem/tp/clearcmos.htm