If you go to to the below site download the download tool and create a bootable usb installer. Google this term ( replace make and model with real one) "make and model boot select menu" this should tell you what key to press at boot to get to the menu to select the USB stick. Go through the motions until it comes up with repair option and see if it will do it from there. It might not be able to do it from windows due to corrupt files. Back up first
It is a shame you are not close as I would install an SSD in it for you as it likely has a mechanical drive (guessing but educated)
https://www.microsoft.com/en-gb/soft...load/windows10
Another thing you could try before all this is create a new user and boot to that. Often users can become corrupt and I have seen many times simply making a new user can fix issues .
https://support.microsoft.com/en-us/...ion=Windows_10
You could also try running ccleaner to clean up everything then hit start and type cmd, when it shows the item right click on it and select run as administrator and then type exactly sfc /scannow this will scan for corrupted system files and attempt to repair them. It might be worth having the windows 10 installer you made earlier as it may need files off it