If your computer has been infected by a fake antivirus / scamware use Spybot Search and Destroy to clear it out. You may have to boot into safe mode. Click Here for more details.

No Virus Protection is 100% fool proof. You must use caution when you browse and download from the internet.

If would like to have more secure computer. I recommend changing your operation system to Ubuntu Linux.

You may still need an expert to install windows applications. This OS is more secure than windows because the software is written in a different programming scheme and most virus/spyware/malware is written for windows.