Virus Shutdown Laptop

I am trying to remove a mean virus from a toshiba laptop. When the laptop starts up in normal mode or last known good configuration it goes straight to “the blue scrren” telling me that a trojan virus has attacked the laptop. When I start in safe mode I have no pointer movementform the pad and even when I tab over to the “start” menu and hit enter I can’t get the programs to list so that I can run Norton. How should I approach this issue?