Faced this problem in recent past. Went over to each and every blog that mentioned the recovery steps. Some were so geeky that i have to study the "Computer Fundamentals" book again :)
But the steps, I am about to tell you are easy to gulp..

1) Download Spybot-Search & Destroy utility from here.

2) Run Spybot after installing (if you don't know how to install, let me know .. i will paste the installation pictures step by step)

3) Click on CHECK FOR PROBLEMS

Once the program completes the checking for problem step, it will give you some errors that it found.. colored in red (like picture below).



You will find the entries related to Task manager and registry. Those are the entries that got corrupted due to this virus. There will be one more like "Autoit.P" and that is the main virus program that is causing the problem.

Click on Fix Selected Problems ... and there you go.. you won't be getting disabled task manager any more...