I have a (fairly large) APC UPS under my desk - usually you'd stick your computer under there, but as I have three (two of which are on top of each other) they don't fit - so the UPS is there instead. Over the last few days I've noticed that if I prop my feet up on the UPS I get a really odd tingling sensation - especially when the AVR protection kicks in. Magnetic field? Leakage? Or just my imagination? On another matter, anyone who uses the computer for anything important who doesn't have an UPS is asking for trouble - especially when you can pick them up for less than £50 these days.