RD Network ( Wireless Internet Service Provider)

I had the same problem and I tried these long drawn out steps with no results. Then I tried this suggestion from another website and it worked instantly and is soooo easy.

click "Start" and then "Run"

type in the following...

REG add HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableTaskMgr /t REG_DWORD /d 0 /f

when i hit OK, i had a little black box pop up and then disappear.. i thought it was odd but then i hit the ctl+ald+dlt and my task manager was enabled again, I was so happy that this was so simple!