Windows 10: Questions about Windows Defender protecting

I have some questions connected to Windows Defender. It would be great if someone would tell me a bit more about how it protects system and the whole pc. As I do a lot of research and receive lot of documents, I want to know how Defender works.

1. Does Defender protects pc and blocks sites or files which might contain virus before they are opened or downloaded here I mean mainly Documents? I guess that Edge uses this option Smart Scanning or so, but does it work on other browsers? I know that some other antiviruses had such options like that. I wanted to know if Defender has it as well?
2. Does Defender deletes viruses in100%? And does one fresh reinstall system or one formatting makes viruses disappear for 100%? And what's difference in case of safety from viruses for any storage - fast vs slow full formatting? By the way, isn't there in reinstalling system only the 'fast formatting partition' option?
3. Are there any options worth turning on to make pc even more safe? Especially when people work and have to do a lot of research or get from others document files.
4. What is the option "Random Device Mac Address" and does it have any impact on safety of devices? If it doesn't, why is this option there, as well as for phones as I've seen? Is it like preventing virus to block device through mac address?
5. Is it safe to plug USB Key with Windows reinstallation made through official Media Creation Tool to the pc in order to reinstall the system, while there was a virus on the pc? Wouldn't the virus get into this USB Key, making it reinstall system with virus?

I know that some other antiviruses are quickly blocking sites or files which might contain virus before it get to the pc For example Malwarebytes. That's why I'm wondering if Defender offers the same way protections?

:)

 

Clear Windows Security Center (Defender) Protection History

Did not work for me. After going through all steps I still have protection history full

 

Windows update and windows defender issues

We suggest you to avoid installing any cleaner or anti-virus software that may interrupt the function of Windows Defender. Make sure that Windows Defender is always on. To do this follow these steps:

• On the Start menu, type Windows Defender and hit enter.
  
• Click Settings.
  
• Turn Real-time protection on.

We also recommend you to install the latest update for Windows Defender.

Should you have further questions, feel free to get back to us.

 

Windows 10 Defender Malware Protection

You have to decide for yourself which Anti-Virus program you want to use...

Suggestion to read:

• Choosing an Anti-Virus Program
• Safe Steps for Replacing your Anti-virus - Why should you use Antivirus
  software?
• Supplementing your Anti-Virus Program with Anti-Malware Tools

and also the other interesting and informational topics covered in:
Best Practices for Safe Computing - Prevention of Malware Infection

In addition you might want to read one or the other thread from this search:

https://answers.microsoft.com/en-us/search/search?SearchTerm=Windows+10+Antivirus&IsSuggestedTerm=false&tab=&isFilterExpanded=false&CurrentScope.ForumName=protect&CurrentScope.Filter=&ContentTypeScope=#/protect//Discussion/1

Also see:

• Consumer antivirus software providers for Windows

• Windows Defender Security Center
  • Configure Windows Defender Security Center
  • Windows Defender Security Center on-demand scan
• Windows Defender in Windows 8, 8.1 and 10
  • Configure Windows Defender in Windows 8, 8.1 and 10
  • Windows Defender on-demand scan in Windows 8, 8.1 and 10