1. Click the 'Start' button. Click the arrow next to 'Shut Down' and click on 'Restart.'
2. Tap the 'F8' key repeatedly as the computer boots up, but before Windows loads, to display the 'Advanced Boot Options' menu.

3. Navigate with your keyboard arrows to highlight the 'Safe Mode with Command Prompt' option and press 'Enter.'
4. Type the following text into the command prompt exactly as displayed and press 'Enter.' The double-quotation marks are part of the command. 'C' is the letter assigned to your hard drive.copy 'C:\WINDOWS\ServicePackFiles\i386\ndis.sys' 'C:\WINDOWS\system32\drivers\ndis.sys'
5. Press 'Alt,' Ctrl' and 'Delete' simultaneously on your keyboard. Click the arrow on the lower right-hand corner of the screen that opens and select 'Restart.' Allow your computer to boot into Windows as normal.