Open Microsoft Edge
Click the three-dot menu
Select Settings
Go to System and performance
Turn off Startup boost
Turn off Continue running background extensions and apps when Microsoft Edge is closed
Open Task Manager
Go to the Startup apps tab
Disable Microsoft Edge if it is listed
Open Windows Settings
Go to Apps
Select Startup
Turn off Microsoft Edge
Open Task Scheduler
Disable any Microsoft Edge tasks
Open Edge Settings
Go to Profiles
Select Sync
Turn off browser sync if it restores startup settings
Check the Startup folder
Remove any Edge shortcut from the Startup folder
Check browser extensions
Remove any extension that forces Edge to open
Run a malware scan
Restart the computer