You can use the power button to restart your computer three times. This will start the Windows Recovery Environment.
"How To Access Advanced Startup Options in Windows 8 or 8.1"
http://pcsupport.about.com/od/windows-8/a/open-advanced-startup-options-windows-8.htm
"How to Boot to Advanced Startup Options in Windows 8 and 8.1"
http://www.eightforums.com/tutorials/4935-startup-options-menu-boot-windows-8-a.html
There is detailed information here too.
http://www.eightforums.com/tutorials/2843-automatic-repair-run-windows-8-a.html
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And please read this method:
"How to Boot to "System Recovery Options" in Windows 8 and 8.1"
http://www.eightforums.com/tutorials/2269-system-recovery-options-boot-windows-8-a.html
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Or see if you can do a reinstall:
Packard Bell: Press and hold the ALT key while pressing repeatedly the F10 key. Release the keys when a message displays that Windows is loading files.
““Using Packard Bell Recovery Management to Restore Windows 8”