I´m a complete ignoramus about pcs so need some really basic help... I have an Evesham pc running on an athlon processor and using XP. Happy with it and all was running well until...I downloaded Norton antivirus 2005 and all continued to be well. Turned off pc and the following morning pressed the power button. PC starts up - witness aircraft noise taking off from the fan - but nothing appears on the screen except "power saving" and no beeps or anything else is heard... Is this as bad as I think? CPU/motherboard failure? What can I do? Is it connected to anti virus?