When you need to repair Windows or something doesn't work properly, you may need to start Windows in Safe Mode with Command Prompt.
Safe Mode means that Windows will start only with essential functions required to load operating system itself, so it will not start non mandatory and/or third party applications.
Using command prompt you can type different commands to troubleshoot, repair or to check system health.
By default, the usual method to enter in Safe mode is to press F8 key (keep pressed) when Windows is starting (before Windows logo appears), but since Windows 8 this method doesn't work anymore - we will use another way.
One method to start Windows 8 in safe mode with command prompt is to keep pressed Shift key while clicking Restart computer(press Shift + Restart).
After you restart Windows 8 with press Shift + Restart, will appear this screen.
Click Troubleshoot
Click Advanced options
Click Startup settings
You will see a preview with options that will appear if you continue. Is what we want to do, since we have Safe mode in list. Press Restart
Now we need to press a number, corresponding to desired action. I will press 6 to start in Safe mode with command prompt
Wait a little and you will enter in Safe mode with command prompt.
Another way is to use msconfig utility, included in Windows.
To do that, press Windows key + R
Then type msconfig and hit Enter or press Ok.
Then go on Boot tab, check option Safe boot and select Alternate shell.
Options listed there means (in case you need something else):
Click Apply, then Ok and then click Restart.
You are now in Safe mode with command prompt.
If you want to exit from command prompt and restart Windows 8 normally, type again msconfig, then hit Enter.
Uncheck Safe boot and now you will start Windows normally, instead Safe mode.
Click Apply, then Ok and then Restart.
To access Safe Mode with Command Prompt in Windows 7, you need to restart the computer and keep pressed F8 key at the initial time when Windows starts (before logo appears). If you miss it, you need to repeat the operation: restart computer and keep pressed F8.
In window that appear navigate with arrow keys, up and down, select Safe Mode with Command Prompt and then press Enter
Is possible that Windows will make a check for some files, you need to wait.
You are now in Safe mode with command prompt
To enter in Safe Mode with Command Prompt in Windows XP, you need to restart your computer.
While computer is restarting, keep pressed F8 key (right at the beginning, before Windows logo appear). If you miss it, repeat the operation (restart computer and press F8)
Move arrow keys up or down, select Safe Mode with Command Prompt.
Then hit Enter.
Windows XP may perform a routine check for integrity of files, just wait patiently.
You are now in Safe mode with command prompt