Try clearing the Windows Store cache and then try again.
I tried to run the tool to reset Windows update and it says it solved the problems but nothing happens.
Windows 8.1 is an update to Windows 8, much in the same way that service packs were updates to previous versions of Windows like Windows 7.
Doing so prior to updating to Windows 8.1 ensures that Windows 8, as well as your computer's hardware, is starting clean. Disable the real-time protection in Windows Defender.
You can do this from the Settings tab in Windows Defender, which you can access from the scan using Windows Defender prior to updating to Windows 8.1.
Click the Download button to start the Windows 8.1 download process.