How can i restart my windows 2000 computer?

My computor has frozen and won't restart normally. I can get into it by going through safe mode ,but when the desk top display comes up it changes to a white screen with a blue triangle in it and I can't reactivate it. Pressing the icons has no effect.I can open things using Ctrl+Esc but can't get anything to work once they're open. I've disconnected the peripherals apart from the wireless router.It's a Toshiba model with Norton anti virus.