Hello Manish,
Thanks for reaching out! I'm an Independent Advisor and a Microsoft user just like you.
Here’s how to uninstall your antivirus:
Press Windows + I to open Settings.
Go to Apps > Installed apps.
Find your antivirus, click the three dots next to it, and select Uninstall.
Delete Remaining Files:
Search for the application in File Explorer, go to its installation folder, and press Shift + Delete to remove any leftover files.
You Can Use the Official Removal Tool:
Download and run the official removal tool for your antivirus, such as:
McAfee Removal Tool (MCPR)
Norton Remove and Reinstall Tool
Restart your computer to complete the uninstallation.
If Windows Defender is Still Not Working:
Go back to Windows Security.
Manage Settings:
Under Virus & Threat Protection settings, click on Manage settings.
Enable Real-time Protection:
Toggle the switch for Real-time protection to On.
Ensure Windows is Up to Date:
Go to Settings > Windows Update.
Click Check for updates.
If issues persist, run the Windows Security troubleshooter by going to Settings > System > Troubleshoot > Other troubleshooters.
This should help you get Windows Defender back up and running!