In about 2016 I installed Bluecoat's K9 Web Protection on this laptop. The administrator password has been lost, but the email used to set it up is still in use. When the service blocked a website I needed access to, I could simply request a temporary password be sent to that address, configure the web filter as necessary, and continue. Around 2 months ago, I tried to do this and found that I would not receive a temporary password. It wasn't too urgent, so I shrugged it off.

About 15 days ago, I was purging some unnecessary items from my start-up processes, and I decided to prevent K9's process from start-up. After this, the filter began preventing access to way more sites than before, including my personal financial services. (!) Deleting the files and removing the left-over registry keys & values via CCleaner have made no improvement. Any advice on what else to try would be very appreciated.