I have two tales of woe to add to the collection here!
Many years ago I used to train people new to IT, someone has mentioned Olivetti 386's, those were the PC's I used to train people with at the time. There was one lady, Ginny. Every time she sat down at any computer it would go totally nuts, the poor woman was driven to distraction and being new to PC's she assumed it was her fault and she would never get the hang of using them.
After a few weeks of this we sat down to talk about what she wanted to do next. As part of our talk she told me that she had been previously 'diagnosed' as having, or creating, a high level of static charge.
So I got her to touch a radiator and sat her down at a PC and away she went, from that point on as long as she earthed herself before hand she had no further problems.
This one is more recent.
In my current role I was moved to a new desk with a new PC. So I packed up all my stuff and moved to my new deck and PC. Set up all my stuff at the new desk, all good so far.
Over the next few days I noticed my typing seemed to be getting worse more spelling mistake than usual passwords not working etc. etc.
I'm a competent touch typist and although we all make mistake at times this was getting silly. So I slowed down to see what was going on and that's when I noticed that certain keys when pressed would mistype ie I'd type a 'p' and get an 'h' and so on. Not every key just some of them.
So anyway I dug out a new keyboard plugged it into its USB port.. Exactly the same issue, I tired different empty USB ports, still no joy.
As a last resort I unplugged a USB powered Plasma Ball toy, a Christmas gift from my girl friend, and plugged the keyboard in there. JOY it worked!!!
Plugged the toy in to another port, problem came back, it was now obvious what the problem was.
Strange thing was it had worked perfectly on my old PC and works perfectly on my home PC when tried there as well. But obviously on my new work PC it must have been causing some kind of interference on the USB bus.
OK, neither one is IT magic, although Ginny thought so in her case.