Warning: spent 6 hours on a laptop that just needed a new CMOS battery
Had a Dell Latitude come in on Monday that wouldn't keep the time or boot past the logo, so I tore the whole thing apart thinking it was the board. I reseated the RAM, swapped the drive, even flashed the BIOS twice, and it still kept losing the date every time I unplugged it. Turned out the coin cell was reading 1.8 volts instead of 3, and a $2 battery from the drawer in my Charlotte office fixed the whole thing in two minutes. Six hours of my life gone over a battery I've replaced a hundred times. What's your dumbest "it was the simplest thing" repair lately?