WHO disabled the task manager?

Is your computer showing error messages when trying to run the task manager? Then you need to look for virus that has done it.
Why can't your anti-virus fix this?
This is because your anti-virus can remove the virus (if updated regularly). But it cannot restore the changes made by the virus.
So here is my Tip to fix the hole and a few softwares which may help you later on ( some small sized freewares).
Yes, its so simple by using the following tools without messing with the registry.

TOOLS YOU NEED....

These are the following tools (softwares) you require to do the operation.
  1. ProcessExplorer
  2. RRT(Remove Restriction Tool)
  3. HijackThis
These are all freeware download links from softpedia.com. These are also small sized softwares processexplorer (1.56MB) and RRT(48KB).
ProcessExplorer is a tool that is similar to windows task manager. Process Explorer will show you information about which handles and DLLs processes have opened or loaded.
RRT (Remove Ristrictions Tool) - A tool to re-enable Ctrl+Alt+Del, Folder Options and Registry tools
HijackThis is a general homepage hijacker detector and remover that targets the methods used by the most common hijackers