System Tool 2011 - How to remove/get rid of it

My computer had caught such an annoying malicious software recently, called "System Tools".
I didn't know where it came from, suddenly it just auto-installed in my computer without my permission.
Then it performed a computer scanning which I later found out that it was fake. It pretended that my computer has been infected with heaps of dangerous viruses as listed by its 'fake scanner'. The interface of System Tool pretty much looks like this

Then it said that if I want my computer to be secure, I need to remove those viruses by installing this software. If I click 'remove' button, it will lead me to a download page where I should buy the software. It even include the 'secure payment' option. Luckily I didn't do that.
But this System Tool was so annoying. It blocked all my applications, then gave an alert message

"Warning!
application cannot be executed. The file cmd.exe was infected
Please activate your antivirus software"



This warning appeared whenever I try to run any application.
I couldn't even run my anti-virus software
Moreover, System Tool changed my desktop background to this

Then I tried to google the solutions. Some of the website I found are:
http://www.2-spyware.com/remove-system-tool.html
http://www.fasterpccleanclean.com/remove-system-tool
and many more. One automatic options they offered is to download another software called 'spyware-doctor'. I tried that but I couldn't manage to install it as System Tool blocked the aplication.
Then a manual solution gave me the instruction to:
1. kill this malicious program, using task manager --> didn't work, as the task manager was also blocked
2. delete the registry values and some files --> couldn't find any of them, or may be i just don't know how to find them and don't even bother to try to find them :p.

Ok, so I'm not a computer expert, I want the quick solution. Then I browse through the comments under one of those website, and I found the simple solution that has worked for me. Just 5 minutes, and my computer was free of System Tool, now back to normal. Here is the solution:

1. START THE COMPUTER IN SAFE MODE
2. RUN SYSTEM RESTORE (it might require you to run it from command prompt)
3. CHOOSE A RESTORE POINT
4. LET THE COMPUTER DO THE REST AND AUTOMATICALLY REBOOT

 voila!!!! System Tool is gone
Good luck