For months now my computer seems to be struggling with some slowness. By slowness I mean applications taking longer to launch, applications freezing, and Windows taking longer to shut down. It seemed like a computer that had become junked up with drivers over a long period of time. And my email client (Eudora) and browsers (Opera classic, Firefox, and IE) seemed to take longer to react to websites. But every time I do a test at Speedtest.net, there is no slowness.
I have Norton Internet Security which is always on. I did a full scan, and it found nothing except a few infected junk email attachments. I never click on these anyway, and just delete all attachments from time to time.
Then two weeks ago my computer slid off my lap down my leg and then fell to the floor. It didn't look like much of a bump, so I was surprised to see a blue screen telling me that Windows had an unusual event and had to shut down. It was also making an image of memory onto my hard disk. I was too flustered to write down the details. So after it was done copying, I restarted it and allowed it to start normally. Everything seemed fine.
Later that day I got a screen that appeared to be a Windows status screen. Not a blue screen. Not an error screen. A screen with wallpaper and nice font, just like the welcome screen. It said "Preparing Security Options." Then after about 5 seconds, it went back to normal. The Microsoft support area contained a question about this message, and the advice was to run sfc /scannow from an elevated prompt So I did. And it said it didn’t find any integrity violations.
I decided to run Malwarebytes. I have the full version but had not run or updated it for months. But it would not connect to update its malware definitions. I used it to scan anyway, and found no problems. I tried to update again, but it would still not update. I checked the settings and noticed the “enable self-protection” was not active. So I clicked that box. Then I clicked the subsetting that says “enable self-protection early start.” When I did that, Malwarebytes disappeared from the screen. I could not start it again. All I get is an hourglass cursor that quickly disappears. So I downloaded a fresh Chameleon from the Malwarebytes website using a different computer. Then I ran every script from a USB drive. It did me no good.
Also, my computer was becoming more and more sluggish and more frequent application freezing. And I noticed a new message when I shut down. It would often say it had to force a task host window to close. And then Norton Internet Security started frequently giving me messages about applications were doing a lot of disc writing. I was not too worried at first because I was either downloading or moving files at the time. But still, I was getting a lot of these. And then I got one for simply launching my email client.
Yesterday my browsers stopped working. Meaning, they would not even try to connect when I clicked a bookmark. If I reboot Windows, they work fine for awhile, then I have to reboot again. I ran Windows Defender Offline and it found nothing.
Malwarebytes has a utility on their site that is provided by you. I was going to run it next, but a friend suggested I come here and ask your advice instead.