As long as you haven't done anything to the Windows Firewall then the rule should be enabled. The rule for Windows Updates is
Control Panel > Windows Firewall > Advanced Settings > Outbound Rule > Core Networking IPHTTPS Just make sure there is a Green Check next to it.
If there is a problem with your Windows Update Cache you can clear it out as follows
- Press WinKey + r
- Type services.msc
- Stop the Windows Update and Background Intelligent Transfer Service
- Delete C:\Windows\SoftwareDistrubtion
- Restart the two services and Windows Update will rebuild this folder