There has been a proliferation of fake virus alert or rogue security software attacks. These programs create a legitimate looking pop-up window that appears on your screen while you surf the web notifying you that your computer has become infected and prompts you to take some sort of action such as: clicking to install software, pressing ok to install updates of some sort, or clicking to remove non-existent virus or spyware infections.
When you click the rogue software actually downloads to your computer and installs itself. Once installed the rogue software can perform any number of malicious activities. Predominantly the software will attempt to lure you into paying for non-existent software to remove the 'viruses' that are infecting your PC. However, this rogue software also will disable your legitimate antivirus software, steal personal information from your computer such as credit card information, and disable windows updates and/or make your computer completely unusable.
If you suspect that your system has become infected there are a few things you can do yourself to try to eliminate the offending software. One very good free tool that you can download, install and use to scan your system is Malware Bytes anti malware. This software does not work in every instance but it is at least worth trying before you take your computer in to have it repaired by a professional.
In most cases the rogue software will not allow you to download antivirus software to scan your system once it has been downloaded and installed on your computer so you may have to reboot your system in safe mode. To boot your computer in safe mode you must first either power your system completely down or perform a reboot. Once you have initiated the reboot sequence to enter safe mode you should press F8 while the system is beginning to power up. It is best to tap the F8 key several times while the system reboots to ensure that the system detects the keystroke.
You should be presented with a screen with several options one of which will be 'safe mode with networking'. Use your arrow keys to select this option and press 'Enter'.
Once you have reached the desktop open a browser and use Google to search for 'MalwareBytes' or type 'malwarebytes.org' into the url bar at the top of the browser.
Download and save the program to your desktop. Close all browser windows. Double click on the program that you just downloaded. Follow the prompts to install the program and use the default settings. Scan your system for all malware and with any luck you will have removed the offending rogue antivirus program. If after having following the preceding steps your system is still infected you may have to consult with a professional computer repair service.