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"

A Silent Lullaby

I was dreaming of your crystal-clear eyes

and the sweet smile from your tiny lips

I was looking forward to the day

when I finally hold your soft little hands

Can't wait to see the sparkle in your eyes

when I finally home and present you a Cinderella's dress,

brought from wonderland, miles away across the ocean.

I was dreaming of the day when you'll first call me aunty,

the sister of your father

then you will show me a dance you learn from school,

with a pretty ballerina dress

or sing me some songs you learn from your mom and dad

But God has chosen a better homeland for you

He has handpicked you to grow up in heaven

where there is no weeping, and no pain,

so you don't have to see injustice in this world

He, who has formed you in your mother's womb,

has chosen you to be His princess

and His mighty arms cover you in grace

Goodbye my dear,

though I've never seen you, I know you have my heart already

sleep tight..., I'll sing you a lullaby

-a lament for my niece-

7 Feb 2011 - 10 Feb 2011