All of a sudden a pop up called “SecurityTool protect your PC” pops up and start scanning your computer and alert you that your computer is infected with Trojans, Malware and Spyware.
STOP from there do not click on Remove button or anywhere else. SecurityTool itself is a Trojan and you need to remove it.
My computer was infected with SecurityTool twice and first time I had to reinstall Windows to get rid of it. I start trying couple of things to remove Security Tool and it got worse and worse. Finally, I could not do anything except to run the recovery partition and install Windows again.
Second time I found a good guide to remove SecurityTool without any problem. If you see a pop-up similar to the following stop playing around with that computer and follow the instructions on this guide (www.bleepingcomputer.com). I recommend you to use another computer connected to internet to open up the guide and download softwares if possible.
It worked perfectly and able to remove the Security Tool successfully. Malwarebyte removes it quite effectively.