Sometimes you are not able to download Windows Update. Without Windows Updates chances are your computer/laptop is not working well.
This screen shows the related issues with Windows Update.
Before getting into more diagnostics and web searches you make sure this service is turned in the Control Panel's Services window.
This service is by default 'Manual'. You can 'Start', "Stop" or "Restart" this service in the Control Panel-> Services node.
If you look closer this Windows Service requires another service "Remote Procedure Call" running.
In the Control Panel's Services node you can 'Start', "Stop" or "Restart" this procedure is also "Manual" by default.
If you have to do any of the above, you must have administrative rights over the computer/laptop.
Even after doing all this if the Windows Update does not work, you should look for other problems.