OK, this may be a little technical but do this.
Open a command Prompt as an administrator, you will find the command prompt by searching for it - use the search box on your taskbar next to the windows menu icon; it should come up like this:
Right mouse click on it and select run as administrator:
A black box will appear on your desktop with a flashing prompt. Left click your mouse next to the prompt and type this (you can copy and paste it if you wish):
sfc/ scannow (note, there is a space between the / and scannow)
press return or enter on your keyboard and wait for the command to finish. This is called the System File Checker (SFC) and checks that all your system files are intact; if it finds any errors it will correct them. It could take a while for it to run, but be patient.
Come back and tell us if it finds any errors
