i discoverd recently that this is because windows left a way to disable the task manager so administrators can stop users from displaying it, it is a simple registry entry, which spyware has now taken advantage of. here is a link to fix it, follow instuctions CAREFULLY, the option is to REMOVE THE TASK MANAGER so you must disable it so it does not REMOVE it, enabling it will tell the computer that yes, you do want to REMOVE THE TASK MANAGER, you know its one of those double negative things.
here's the site:
http://www.windowsnetworking.com/kba...XPHomePro.html