Here's How:
Now for Safe Mode:1, Boot normally with the Windows 7 DVD in your CD/DVD drive. When prompted to 'Press any key to boot from CD DVD....' just press any key.NOTE: You only have 8 seconds to take action
2, Select your regional settings & click 'Next' to continue3, Click 'Install Now'4, Click to accept the terms of the licence agreement then click 'Next'5, Select the type of install and click 'Next'6, Click 'Drive options'7, Click 'New'and enter partition size then click 'Apply'8, Click 'Next' to start the copying process of the installation9, Install will restart after the copying process has finished.
1, Before bootup, press F8 to enter the boot menu2, Select 'Safe Mode' and the boot process will begin3, Once booted you will be presented with the following warning
NOTE: Do not click 'OK' or press Space/Enter4, Press SHIFT+F10 to open the Command Prompt5, Type compmgmtlauncher into Command Prompt and press 'Enter'
NOTE: It can take a few seconds to display Computer Management6, Click on 'Device Manager'You can now disable (not uninstall) any device that you believe is causing the failure to boot