I recently PAT tested 2000 items at a local secondary school, including lots of computers.
Our stickers all had our company name, a barcode and a number so you're right, that info is no help.
We didn't test personal electrical goods, just stuff belonging to the school, but requirements may be different at your Uni.
This is the one I use, it's probably the one that fella had as well.
If he used the wrong test he could have passed 500 volts through your PSU, which certainly wouldn't have done it any good.
However, it's probably just a coincidence, thinking about it, otherwise there may have been instances of computer failure all over the site.
And, sorry to say, but on studying all the evidence, it does kinda point to the PSU. Do you not have a friend there with a desktop computer who would let you try using their PSU briefly?