There are at least two options: first one is the operating system is broken; second one is your hard drive has bad sectors. Both cases you need to run full hard drive diagnostics, including the hard drive surface test (bad sector repair).
Restart your computer and do not use windows
you restart the computer then turn it on again
Restart your computer
restart the computer
A good way to check to make sure the computer registry was restored is to restart the computer. If the registry was restored, the computer will restart with no problems. If the computer shows a screen that offers the user a choice of options like restart normally or restart in safe mode, there could be a problem in the registry that the computer needs to fix before restarting.
Restarting a laptop computer is just like restarting a desktop computer. If you are on a windows computer you go to the start button in the lower left hand connor of your screen. Click on the start button. Click shut down computer when it bring up a box that gives you may options like shut down, restart or log off. Click the restart button. If your on a mac computer, go to the top left hand connor, click the apple picture than click restart. If your on a Linux computer go to the top right hand connor and click the power button, then click restart.
To change a host name in Windows XP, click start, control panel, performance and maintenance, and then system. From the system screen, click the computer name tab, enter the new computer name in the dialog box, and click OK three times. Restart the computer for the change to become permanent.
To restart your Windows 8 PC swipe the right side of the screen on the desktop or put you cursor in the bottom right hand corner of the screen. A menu should appear with 5 icons; select the gear for settings. In the next menu that appear you should see a power option. Select that and in the drop down menu select restart. Your PC should restart.
just refesh the screen or restart the computer
To do a Windows update on your computer you can go to the Windows icon on your computer screen. Click on it and go to the Updates section. Click on Updates and follow the instructions.
A screenshot on a Windows XP computer may be done by pressing the 'Print Screen' button, or on a Windows 7 computer by navigating to Start Menu > Accessories > Snipping Tool in addition to the 'Print Screen' function.
Blank screen: windows lose activation Other: press f8 and disable automatic restart on hardware failure