You will get task manager disabled message in following two circumstances:
1. When you right click on task bar
2. When you run taskmgr.exe manually
So, why does this message comes?
There can be mainly two reasons:
1. Administrator disabled it manually.
2. Your computer might be affected by virus/malware.
If computer is affected by a virus, run an up-to-date anti virus scanner that will find out infected files if there are any.
After scanning for viruses, you can go through following process for enabling task manager-
For Windows XP Professional Users:
If you have Windows XP Professional, Click Start, then click Run and type in gpedit.msc:
And press OK. This runs the Group Policy Editor.
Once in the Group Policy Editor, expand in turn:
• User Configuration
• Administrative Templates
• Ctrl+Alt+Del Options
You should see something much like this:
Double click on Remove Task Manager to change its setting:
It should be enough to click on Not Configured and then OK and Task Manager is available once again.
Note: This post helps to enable task manager in Windows Vista/ XP using Group policy/gpedit.
To know how to enable task manager in Windows Vista/ XP using Registry/regedit CLICK HERE.