Hi, good day! I'm Jerico T., I understand that you're having some issues right now, I'll do my best to help you with your concern.
Do you happen to remember if you downloaded and installed any application? Reason Cybersecurity might have been installed on your computer via files bundled. No worries, it's not a virus and we can uninstall it. But before we uninstall it, let's boot your computer to Clean Boot state to prevent any third-party applications in interfering to the removal of the software. Click the link below for the steps.
https://support.microsoft.com/en-us/topic/how-t...
Once done, restart your computer and perform the steps below.
- Press Windows key and search for Control Panel.
- Click Uninstall a program.
- Find the Reason Cybersecurity and right-click on it then click Uninstall.
- Restart your device and try to access Windows Defender.
Please do let me know if you need any further assistance.
Hope this help. Have a good day.
Thank you,
Jerico T.