I don't even know how to do any of that. I know nothing about anti virus software or how to install it. I just want my computer back!
Purchase a decent package to protect you from malware.
Pick one
Kaspersky Kaspersky Lab US | Antivirus & Internet Security Protection Software
AVG AVG | Virus and Malware Protection | Privacy Protection | PC TuneUp (A good free one)
ZoneAlarm Firewall Antivirus Software and Computer Security Suite by ZoneAlarm
I can't afford to pay for anything, so I choose the free ones. I have Avast which obviously isn't working, so I might try AVG and see if that works.
I wonder if I should uninstall Avast first...
There is a free version of Malwarebytes but it is reactive and not proactive.
The problem is that if it is virus related, you could be deleting the operating system so you really need someone more computer savvy to know what to look for and to do or else you will be reinstalling your operating system.