Howtogeek posted a guide about using the Safe Mode to fix your Windows PC

When Windows boots, it normally launches its startup programs and loads the hardware drivers you have installed. If your computer is infected with malware or has unstable hardware drivers that cause blue screens, Safe Mode can help you fix it.

In Safe Mode, Windows uses a very low screen resolution, doesn’t initialize much hardware support, and avoids loading third-party startup programs. This allows you to troubleshoot Windows without all the third-party software and potential hardware driver problems getting in the way.

If there’s a problem with your computer and you can’t seem to fix it — or if your computer is unstable and keeps crashing or blue-screening — you should drop into Safe Mode to fix it.

  How to Use Safe Mode to Fix Your Windows PC (and When You Should)