Microsoft has disabled the F8 key so you can no longer boot Windows 10 in Safe Mode right after powering on your computer. Safe Mode (although it's no longer called that) is still available but is only accessible if you explicitly asks for it when running Windows (there are plenty of articles that explain how this works). Windows 10 also has a mechanism for detecting boot problems and will automatically start in Safe Mode if normal startup is no longer possible. But what if you're not able to start Windows 10 the normal way, and the detection mechanism doesn't work? You can then opt to boot using a Recovery Drive (can be a DVD or USB stick). Or, you can simply re-enable the F8 key... (needs   ...