Task Manager Doesn't Help Errors

Rebooting doesn't help.

I logged in only to see all my files corrupted. Even Avast wasn't able to stop this corruption. Which makes since it's just an antivirus. All my files (except for System32) were turned to a .html file. I was hesitant to click it but I did. The computer screen flashed black and white very quickly. I had to look away because it hurt my eyes. I looked back at it for a split second. Still flashing black and white. I decided to turn off my computer. But it wouldn't turn off. Was this just a sick joke from Microsoft? Did somebody hack my computer? Did one of my friends send me a malicious app? I had no clue. All I know is that if this continued my computer would be spare parts. I took it to a computer shop. They said they had never seen anything like it. So I left. I tried to enter safe mode. But that's literally impossible on a laptop. My computer's fan started making a very loud noise it was like one of those really big fans. My computer over heated and turned it's self off. I called one of my friends the conversation went kind of like this. 'Hey dude my computer is being weird'. Friend "How so?" Me ' Well I was trying to sign into xfinitywifi yesterday and I got a weird error message.' friend " Which one?" Me 'Error 403 forbidden' friend "ooh what did you do after wards?" Me ' I used task manager.' friend " oh crap I gotta go dude bye!" Me 'bye...' That wasn't very helpful. So I looked it up again. Still nothing. I hadn't have high hopes after this. I was still pondering whether I should throw it out or not. I didn't think I should considering there was still a bit of life still left in it...