Windows 8 system freezing can be characterized by not functioning of some controls. For example it might be impossible to execute such commands as clicking on buttons, closing of windows or scrolling in the task manager. This can happen to a computer after updating some applications. If you are facing a similar problem, you should do the following:
1. Perform a System Restore. For Windows 8 you should open ‘Charms’ bar on the desktop using ‘Windows-C’, select ‘Settings’ – ‘Control Panel’. Then select ‘System and Security’ and again ‘System’. After that select ‘Advanced System Settings’ on the right. When a new window opens switch to ‘System Protection’. Click on ‘System Restore’. Select one of the options to restore a previous system state. Reboot your PC.
2. Turn on Hyper-V. Open ‘Charms’ bar on the desktop using ‘Windows-C’, select ‘Settings’ – ‘Control Panel’. Select ‘Uninstall a Program’. Then you should select ‘Turn Windows Features On or Off’ on the left sidebar. ‘Windows Features’ window should open. Check the ‘Hyper-V’ box on it. Reboot your computer.
3. Upgrade your video card. Check if there is a video card update released. Install it. If this does not solve the freezing problem try installing a previous version of the video card drive. Freezing might be due to the latest driver version.
4. Check if your systems files are not corrupted. You should press the Windows key in order to go to the Start screen. After you are there enter cmd. Open ‘Command Prompt’ listing by right-clicking on it. Select ‘Run as Administrator’. Accept the UAC Prompt. The last thing to do is to enter sfc /scannow. If this does not solve the freezing issue, do the next step.
5. Sign out and in. You should press the Windows key and open the Start screen. After that right-click on account name and profile picture. Sign out. Then select the account and log in again.
source: ghacks.net