I started my day at ITS with a similar task that I had in my summer internship: gathering PC serial numbers to make an excel spreadsheet for a list of parts. Most of the computers were missing components such as hard drives and power supplies, however a few of them would not boot at all. By the time I left for the day, I had a list of serial numbers and parts, and had begun running hardware diagnostics on the machines that would not boot.
The most troubling PC had an issue where it would not even start the BIOS. Once the power button was turned on, the fans would start up, shut down, then start up again. This kept going on until the power was turned off, and an image never appeared on the monitor. After opening the tower, roughing it up a bit and taking a look inside, there was nothing to be found that could explain the problem. My instincts told me that it was a power supply issue. However, once the tower was closed up and plugged back in, it started up like it was supposed to. The problem may not have been solved permanently, but at least it was working for the time being. Sometimes all it takes to get a trouble PC working again is a little tough love.