✔ 最佳答案
There could be many reasons. Try the following in this order:
Insert your Windows CD. Click Start. Click Run. Type sfc /scannow and enter. Computer will run for about an hour, depending your speed. This will repair all corrupted major Windows system files including Windows Explorer that controls launching and closing of your programs. Reboot and try. Good luck. Other Windows systems are similar. This is an example for Windows XP.
Make sure you leave a space after SFC