somewhere down the line malware was installed on the computer. sometimes pop up comes up on your computer. if you can, don't click them and use alt tab to cycle through windows and Alt f4 to close them. As far as the problem you are having now. if you are able to get on the computer start it up in safe mode and try to run a system restore to a point before july. do not pay the people the $300. worse case scenario you will have to reinstall your operating system to restore it so that it will not have the malware on it. if you can back up all important data asap before you attempt these repairs. I hope that this helps solve your issue