Task manager doesn't come up

I’ve heard it might be a virus but i’ve checked and found nothing. When I right-click on bar at bottom the menu comes up but when I click on task manager it just disappears, no task manager. Any ideas?
Thanks.

What OS are you using? I believe the right click on taskbar thing came about with NT, so you should be able to bring up the taskbar by pressing ctrl+alt+del.

I am using XP and oddly enough ctrl-alt-del does nothing now, not even reboot.

My computer has occasionally done this, usually after several weeks without rebooting. I’ve found that a manual reboot solve the problem quite nicely.