I have an american xbox that I'm using in Europe (South Africa actually but the power/tv systems are the same).
I've switched from NTSC to PAL with no problems and recently replaced the original power supply with a switchable power supply from Lik-Sang.
Everything worked fine until recently. When I attempt to power up my xbox I can hear a fan (or disk drive) spin up, which stops after about a second. None of the power leds go on and the xbox remains switched off.
However if I keep trying, occasionally the xbox will boot up and operate normally. Also the time that the fan/drive spins for varies.
If anyone has any advice as to what the problem could be, and how to rectify it, I would appreciate the help.