Help with the AV security suite virus!!?

I have the AV security suite virus, and I am trying to remove it. RIght now I am using my sister's laptop. I tried starting it in safe mode with networking but Cisco is retarded and wants me to enter a pword that I don't know, so I copied the installer over on a thumb drive, but when I try to install it on my computer, it says the Administrator has made it so I can't install it. How do I fix this.