Any help in investigating & resolving the following appreciated ... not sure what's going on ... just started today, everything was alright before, and nothing (knowingly) changed ... on a machine with Win XP Pro SP1, it boots OK with normal boot messages flying past, then Win starts and it looks OK, mouse works, but as soon as the Win XP start up screen with the moving blue dots finishes, everything goes dead it looks like the connection between the machine and the keyboard/mouse & monitor stop working because there is just a black screen and no response to keyboard & mouse - also the neon on the monitor goes off I tried another monitor, keyboard & mouse but same problem. what's happening? how do I investigate when I can't see anything? is it a virus (the machine has got an up to date copy of Norton AV)? motherboard failure? power issue?