So I have the Dell Optiplex GX520 and I download the Bios Update. When I install it ran fine then seconds later it said incompatible processor and wouldn't let me do anything and it just sat there. So I restarted the computer hoping be able to get into some kind of command prompt or recovery console but nothin came up it still said Incompatible Processor with the line blinking not do anything else.

What are my options to get the BIOS back to normal and for me to able to run windows xp Pro on my computer.