I think the multiupload link is to download a "helper" application. I would definitely recommend
not installing any additional (and unnecessary) software in an attempt to solve this problem.
If you look at my earlier posts, I clearly identified the cause and the solution to this problem. Something in the System Tray (far right end of the Taskbar next to the clock) is sending a notification and demanding attention. Click the Up arrow
(Show hidden icons) and hit Customize. You need to change the setting for the particular item that is causing the problem to "Hide Icon and Notifications."
You only need to change the properties of the one icon that is causing the Taskbar not to hide, but if you change them all, that will
definitely solve the problem. Then you just need to do some trial-and-error to find out which one is the culprit. I used a bisection scheme to zero in on the cause -- hide half of them, and see if that fixes it. If it does, the problem is being caused
one of the icons in that group; if it doesn't, it's one in the other group. Then hide half of the group containing the problem icon. Continue hiding half of the offending icons till there's only one left.
This is the solution that worked for me. If it doesn't work for you, you have a problem that I can't solve. At any rate, I've said all I have to say on the subject, so I'm unsubscribing from this thread.