Here are two ways you can accomplish this task. Let’s look at them.
Go to User Configuration > Administrative Templates > System > Ctrl+Alt+Del Options.
Double-click Remove Task Manager in the right pane.
After selecting Enabled, click the OK button at the bottom.
Note: To enable Task Manager, follow the steps above but select Not Configured or Disabled.
Now navigate to: HKEY_CURRENT_USER > Software > Microsoft > Windows > CurrentVersion > Policies.
Click on System. If it’s not there, you’ll need to create it.
Here’s how: Right-click on Policies. Select New > Key. Enter System and then press the Enter key.
Right-click the blank space in the right pane. Select New > DWORD (32-bit) Value.
Enter DisableTaskMgr as a name and then press Enter.
Double-click on this. Provide 1 in the Value data field. Hit the OK button.
Sign out and then sign back in.
Note: To enable Task Manager, change the value from 1 to 0 in the DWORD or delete it. Make sure to log out and then log back in.