Windows 8 computer wont really boot after viruses and malware were removed

[MatthewStewart]

My buddy had constantly downloaded unsafe movies and went without an antivirus or anti malware program for like 6 months and his computer was running very slowly. So yesterday I installed anti malware and avast antivirus, the malware scan detected 556 infected programs so I removed them. Avast found 1 virus and I quarantined it. I restarted the computer so anti malware could finish its removing process and when I rebooted the computer it took a while to start and froze when I hit the main screen, then unfroze but went very slow and froze again, So I shut it off. I cant get it to log in anymore without having an infinite welcome screen, or just a black screen but usually I can get to the user screen without problem. I don't really have anymore information on whats occurring however one time I booted there was a blue screen that said "a problem was detected with windows for more information search this up: Driver (there was more to follow This but I didn't catch it)". If anyone could help me I would be very grateful, I'm the reason why he cant use his computer and I really don't want to purchase him a new one. - Thanks Matt

 

[Tmagic650]

Re-install Windows fresh...

 

[Benmar]

Try to repair your windows using windows 8 CD..