I would guess, as you did, that the issue is this
web rooter. To get to it, you can try:
1. Press alt+tab. Hold down alt and keep tapping tab. You
should either find a "web rooter" window or similar, or
eventually get back to the first window you had open. Most
anti-virus type programs don't have a window open so this
won't necessarily find it, but it's the easiest first step.
2. Press WINDOWS+B to move the focus to the system tray (B
for... because :) I don't know, it's Microsoft's shortcut).
Next, press right arrow to move through the icons and see if
you can find it there. If you have "notification chevron" or
"notification overflow" or similar, press up arrow, then use
left arrow to move through those icons.
When you find it in the system tray, press applications key to
bring up a context menu then down arrow through that,
alternatively try enter or space.
Look for something like "Exit".
Failing that, press control+shift+escape to bring up task
manager and down arrow through the running programs to find
it. If you press tab and find a "more details" button. Press
enter to show more details. When you find web rooter, you can
press alt+e to end task (or context menu then find end task).
Be sure you are exiting the right app as this will force close
it and it could have unintended consequences if you close the
The other thing you might want to do, if you don't want
this web rooter, is to open the start menu, type "add or
remove programs" and see if you can find the program to
uninstall. Note it is a good idea to have an anti virus
program of some sort running. On Windows 10 I just use the
built in defender, but there are third party ones which work
as well. At some point before uninstalling it, you might
check and see if you can access the main program window or
functions of this web rooter and see if you can access it. If
you can and you want to keep it, then you'll just need to
figure out how to disable it while installing programs. If
it's not accessible, it's always worth shooting an email to
the program developer to ask them to make it accessible. Even
if you aren't intending to keep it, your request might
encourage them to make the program accessible for others (or
for you down the track).