Thanks for your help in advance!

Here are my problems.

I unplugged my external monitor for a couple of hours and this happened:

1. I cannot adjust screen resolution back to 1600 x 900
2. Whenever I type, hitting the backspace key till the area to erase just sits still until I hit it one space at a time.
3. I am now seeing the thumbnail previews when my mouse moves over the program that is in the taskbar - I never saw this before.

Normally, I can fix things like this on my own, but, seeing that it is Windows 10, I'm still learning it.

And, is there a way to disable the thumbnail preview without changing the registry? I've been searching online and every site that I find tells me to do so.

Can someone help me please! It is interrupting my work because I cannot concentrate, plus, not being able to erase a sentence or even a couple of words is giving me a headache - literally.

Thanks so much!