I have an Optiplex 740 that suddenly quit working. Initially it was showing codes 3+4 indicating a memory error. After trying all the normal stuff I bought new memory... now I get just get a 4 in the diagnostic lights, which according to the manual is a bios issue and they recommend running the bios utility. Problem is I can't boot to run anything. Tried powering off, unplugging, removing battery, etc, to no avail. Any thoughts or suggestions?