Need help with computer please!!!?

My laptop just went down because I went on the web and Mozilla firefox closed now every time I try to access Internet malware protection pops up and says my computer is infected, but my protection isn't malware it's mcafee and it just popped up. So now I try to restore or go back a update time where it was good and malware keeps shutting it down I can't sign up for malware because it's not free please can anybody help?!!!