I was using avast, and late in the night it was blocking every website I went to, so I tried to turn of the web shield. It kept giving me an error 500/501 message, so I ran the uninstaller and rebooted. My computer is super slow, and I can't do a thing. I ran appzapper on avast (which wipes all related files) reinstalled MacOS, upgraded to Mojave, ran disk utility (Each which took around an hour due to the computer's unresponsiveness) and still no luck. What do I do? I don't want to lose all the files on my 4 year computer.