Although I do my best to keep an open mind with issues, as making any assumptions can lead to going down the wrong path, I don’t immediately think the issues you’ve mentioned here are specifically related to the result of installing Messenger 8.5.
By design, anything that calls Messenger’s API will start the client. So, any other software you might run that integrates with Messenger in some way, as some examples, Windows Live Mail, Outlook Express, some older antiviruses, and maybe even something related to Spotinger you might be doing? Of note just sending the window messages to change the song title in Messenger is not calling the API and won’t start Messenger.
Additionally, you cannot use msconfig to disable Messenger starting at startup (in modern Windows versions, it will readd itself, in XP it won’t even do anything). To fully disable Messenger from Windows startup, it needs to be done in the Messenger’s options screen, which I believe you’ve already done - this still won’t affect other applications from starting it though.
It is unlikely Messenger could cause this behaviour you’re describing. Messenger is very much a “user mode” application, does not have a service, or kernel mode components or run with administrator rights. It cannot “touch” Chrome or Windows networking (proxy settings notwithstanding) and has no fancy display components (like DirectWrite).
Yet another crash.
All that said, I have some initial suggestions for you to better isolate the cause of the problem:
- Remove the antivirus
I’ll spare you all my thoughts on antivirus for now, but the short version is that it’s a leading cause of crashes, causes more issues than it fixes and is unneeded for most people. You can always reinstall it later once it’s been ruled out as not the problem.
- Run a memory diagnostic
Having bad RAM will cause random crashes. Search the start menu for the Windows Memory Diagnostic (\windows\system32\MdSched.exe) and allow it to reboot and do a memory test (usually takes 10-15 minutes). The results will show up in a balloon or in the Application event log.
- Check drivers to see if there are updates
Specifically display/graphics and networking.
- Uninstall Messenger
As you believe this is the cause, test to see if that’s the case. Even better, use System Restore to a restore point pre-Messenger install.
- Try another browser
Try using Firefox, Edge, IE or some other browser and see if watching YouTube results in the same thing. Note that a lot of browsers are Blink (Chrome’s engine) based, like Vivaldi, Opera and others, so those may not be a good test.
Also, a lot of these possible issues should be causing blue screens. Are you getting any?
Finally, you may want to check the Application log in the Event Viewer for some of these crashes (event 1000) to see if there are any hints there, sometimes the Faulting module name can give some direction. In addition, you could also use something like procdump to get a crash dump of the application to analyze, but I doubt that would be beneficial based on what you’ve described so far.