The BIOS shouldn't need to be flashed unless the board has been sitting on a shelf for five years. If that's the case, someone sold you a technological Edsel. LOL And the 'BIOS clock' is the real-time clock onboard. As long as the battery is good, set it and forget it. If you want to talk about a Jurassic computer, my sister-in-law dropped off the PC she uses at the church she keeps the books for and designs the Sunday service programs on, so my wife could replace the gimpy CD-ROM. She put that fossil on my workbench, booted it up, and it had a whopping 32 MB of RAM. We tithed a spare CD-ROM drive and an extra 32 MB we dug out of my RAM jar. Working 72-pin SIMMS are a rare commodity nowadays. LOL

First, I tried using an older keyboard and mouse (ones with the round hole and the pins in them) and they did not work either.
So I did that thing with the battery, and the keyboard works during the boot!
I went into the BIOS and told it to enable USB keyboard and mouse. After that, the mouse still did not work.
I took the battery out several times, and still the mouse is dead. Also, the keyboard seems dead after the boot - when windows wakes up.
What now?