diagnostic lights indicate possibly corrupt BIOS

[CosmicJest]

Hello,

We have a four-year-old Dell Optiplex 980 small form factor computer in my office which refused to boot the other day when I wasn't here. The diagnostic light pattern I was given indicates that lights #1, #3, and #4 lit, but not light #2. When I looked at the pattern in Dell's service manual, that particular pattern was not listed! When I tried to boot the computer this morning, I got the same pattern the first time, but the next two times I tried to boot the computer, the pattern I got was lights #2, #3, and #4, which indicates that the computer hardware is operating normally but the BIOS may be corrupt or missing.

One more boot attempt, and the computer booted normally. I'm doing a current backup right now.

What tests/diagnostics should I run to track down the cause of the problem and/or prevent it from happening again?

 

[fireberd]

First, be careful as there is no backup or recovery from a bad/corrupted BIOS on a Dell. On consumer Dell's there are hardware diagnostics accessed by F12 at power on. Not sure if the commercial line has this. If it does you can run a full battery of hardware tests (but it doesn't test the BIOS).

Do you get any beeps at power on? That may help in troubleshooting.

You can try resetting the BIOS, and maybe even replace the CR2032 CMOS (BIOS) backup battery. To fully reset the BIOS, with the PC powered off, open the case and remove the CR2032 battery for at least 10 minutes (Intel says 15 minutes). Reinstall the battery (or a new battery) observing battery polarity. Power on and see what you get. If there were any custom settings in the BIOS they will have to be reset. F2 at power on accesses the BIOS.

 

[CosmicJest]

No beeps at power on. I reset the BIOS by removing the battery as you suggested. I'll keep my fingers crossed that this will be the end of it. Thank you, fireberd!