It's the worst feeling when your computer just won't turn on.
In this case, this older Dell Optiplex would turn on...briefly - Just for a second and then off. The customer was concerned that it may have been a power supply, but wasn't completely sure. Luckily this was a secondary machine so it wasn't absolutely time-critical that it wasn't working, but I went ahead and disassembled the unit, and tested with other known good parts to filter down to the exact issue.
It turns out the motherboard had developed either a highly corrupt BIOS or had some other failed component. The good news here is that despite having a significant number proprietary parts, Dell made a very significant number of Optiplex 7010s, and parts for them are very plentiful, so a replacement was soon on the way.
Anecdotally, the thermal solution that had cemented the cooler to the CPU was the toughest, most stubborn dried paste I've ever encountered, and it took a significant application of spudger, isopropyl and elbow grease to clean it off.
Luckily other than that it was pretty straightforward. A straight swap and replacing all the components, and everything tested out!
Plus, this user was running Linux Mint, so there wasn't even an issue with Windows Activation!
