Have you run an anti-virus scan recently? I wonder if you have some malware in the background that is causing a multitude of problems.
The first thing I'd look at is to see why it's taking so long to start an app after logging in. Once you're at the desktop, can you right click the taskbar and select "Task Manager", then click "more details" in the bottom right (if it's there) and then click the "Start-up" tab.
This will show you everything that loads once you've logged in to your PC, along with the startup impact. Could you please sort this list by "start-up impact" and then attach a screenshot please? Here's a tutorial on how to take a screenshot (
https://www.windows10forums.com/articles/how-to-take-a-screenshot.22/).
Hopefully we can find a resource hog in that list and prevent it from running. We can tackle the other problems after that.
