Try using the cmos jumper to reset the bios with the system off, or remove the battery with the power supply unplugged. You may also try disabling the "spread spectrum" setting if you can get into the bios using the "del" key. I would never flash the bios of an oem motherboard. They are either too expensive or difficult to find, and rarely do bios updates support faster cpus with the oem boards. Hp and compaq websites will list suported cpus on their websites if they are available for your system.