I've just tried the Win key and ; and my emoji keyboard came up and I'm fully up to date with my Win 10, although I don't have the Windows Feature Experience Pack.
It may not have been one of the updates.
In System Restore was there an option to check the box to show more restore points.
Rather than a reinstall you can perform a repair install which doesn't affect personal stuff or installed programs, but before I take you through that, open a Command Prompt (Admin) and enter these cmds and then try those key combos again.
dism /online /cleanup-image /restorehealth
sfc /scannow
Enter exit to close the cmd window.
To perform a repair install you will need Win 10 install media.
You can create either a bootable DVD or USB after reading -
https://www.microsoft.com/en-gb/software-download/windows10It defaults to creating the USB and I've found it best to insert an USB before downloading the MCT.
With the install media inserted, open Windows/File Explorer - This PC and double click on the media's drive.
This will start the process if using a DVD but will open to the files when using an USB where you would then double click on setup Application.
I think this took about 4hrs on one of my machines.