Welcome to the forums, newcomer!
Yes you're advised to use a 2nd Gen Intel processor to update the BIOS with the latest version before dropping in the 3rd Gen Intel processor. Given how old the motherbaord is, you're best off sourcing a 2nd Gen processor to test out the board and if it's worth flashing the BIOS on, verifying that it's not dead. You could take a look at your motherboard's manual, page 3-36, section 3.10.3 - Asus CrashFree BIOS 3 utility and follow through the instructions laid out, though your results might vary with success or failure.