I just restore my laptop, and now i noticed that my usage is above 50% and the major usage is because of explorer.exe which showed 49-53% in Task Manager.

Is that normal? Is there any solution to lower down the usage for explorer?

You can try to use a clean boot for troubleshooting.

http://support.microsoft.com/kb/929135/en-us

You can also use the Windows Performance Toolkit.

http://blogs.technet.com/b/yongrhee/archive/2013/10/15/tool-windows-performance-toolkit-xperf-wprui-and-wpr-updated-version-as-of-aug-2013.aspx

You can also use the Refresh your PC without affecting your files feature.

http://windows.microsoft.com/en-us/windows-8/restore-refresh-reset-pc

Hi,

For high cpu usage issue, I usually use Process Explorer to troubleshoot, here is a link for you to download:

Process Explorer v15.40

http://technet.microsoft.com/en-in/sysinternals/bb896653.aspx

It's a simple and small tool, once you installed and open it, locate to explorer.exe, you will find all processes related with explorer running in your system, find the culprit of the high cpu usage.

Process Explorer Mini-guide and Screenshots

http://www.bleepingcomputer.com/forums/t/354690/process-explorer-mini-guide-and-screenshots/

NOTE This response contains a reference to a third party World Wide Web site. Microsoft is providing this information as a convenience to you. Microsoft does not control these sites and has not tested any software or information found on these sites.

Regards