What a lousy experience. I spent today at a customer doing network upgrades all over: XP/SP2 installs, loading all the latest patches, spyware scans, etc. The works.
I spent a lot of time on the boss's laptop, and to top it off ran a FlashBIOS update on his Dell Inspiron 8100 laptop. Dell has a great system to flash the BIOS from Windows, so there's no need to boot from a floppy drive (which this machine doesn't have). I do this all the time.
After rebooting, the system reported that it was indeed running the A15 firmware (instead of A12), but the keyboard was unresponsive — both the laptop itself and an external keyboard — and the "booting in <N> seconds" message took 5 minutes to count 30 seconds.
This was hosed long before the hard drive was involved, so it smelled like a bad FlashBIOS update, but it all ran properly. I was left with the sinking feeling of being the guy who had his hands on the system all day, updating this and that, but "I didn't break it". It's a lousy feeling.
I took it all home with the intention of trying to find a way to flash an older update, or at least copy the boss's date from the hard drive, when it all started working. Huh?
It turns out that the problem was a bad battery. This is a four-year-old machine, and both batteries have no juice left. The owner uses it in a docking station at home or at the office, and had no reason to replace these dead batteries (he didn't have any idea they were dead).
What I assume happened is that one of the batteries has failed beyond full drainage, and that it's always been bad. The A12»A15 BIOS update treats the battery differently, and this is what hung the system. I have a different Dell laptop which uses the same batteries, and it was just luck that I tried shuffling them around: one battery hangs the system in realtime, every time, whether in the BIOS or in Windows. Removing the devil battery un-hangs the system six seconds later, every time.
Everybody who's worked hands-on with lots of customer equipment has had the experience of things breaking, and the implication that it was our doing. Sometimes it is our doing, but when working on troubled equipment, we get the attention when things go wrong.
It's nice to have iron-clad proof that it's not our doing.