Is Windows Defender a good enough anti-virus program?

It's best to have a 3rd party antivirus program. They have much higher detection rates than Windows Defender. Nothing is perfect though. I recommend having a plan for when your PC is badly infected. Like having backups as eric suggested.

2

No.

Windows Defender only provides a very basic level of security protection. A third-party antivirus program provides much better protection than Windows Defender, Microsoft's built in antimalware/antispyware. I would recommend using McAfee and Malwarebytes together (unlike McAfee with another AV, running McAfee and Malwarebytes together does not cause conflicts) as a best third-party security protection - McAfee for antivirus/security and Malwarebytes for antimalware.

Some people may differ with me, but honesty I don't think so.

I am using AVG free2015, SuperAntiSpyware, and

Malwarebytes. Also Ccleaner. I also turned Windows

defender off.

the best antivirus protection is to buy an external hard drive back up you media once a month and if you get a virus you can reinstall your operating system. after many times of losing my prized media possessions it very freeing to be able to download any file i want and if i get a virus i can reinstall and have my computer back to normal within an hour

The mentioned Windows Defender is a basic line of security, after all, securing your system fully also relies on your sense of security.