It was a USB memory stick that caused my problems. PC would not boot and I couldn't figure it out. Happened to glance at the back of the PC and the fault lights were lit up (its a Dell PC). Took out the stick and all was fine except the memory stick doesn't work anymore I can write to it but the data is all corrupted. I'm bloody annoyed cos it was a 2gb sony one but at least its nothing I did to it! It was just sitting in a drawer. Wonder what happened to it