Your notebook has a CMOS jumper?
BIOS ROM ImageI found this:
Method for a HP BIOS RECOVERY:Prerequisite:
The BIOS recovery procedure requires a USB diskette drive and a formatted diskette.
USB pen ----> doesn't work
Download you BIOS from HP, please note the model 68xxx
Copy the bin file of the BIOS on the diskette. eg:68YHV.BIN and not ROM.BIN
Press the 4 arrow keys (up, down, right, left) on the keyboard and power ON.
Wait ~2, 3 seconds an release the keys.
Wait the end of the process ( 2 minutes)