Luckily it's not that difficult to do
Fix Windows Security Not Opening on Windows 10 and 11
It’s frustrating when you want to run a virus scan on your PC and the Windows Security app won’t start. Several things can cause the app to behave this way. However, there are a few troubleshooting steps you can take to fix the problem.
Some reasons why your Windows security app won't start include the app's configuration being incorrect, your Windows version being outdated, Windows system files being corrupted, and more.
Windows Security won't start because you're using another antivirus program on your PC. That tool might be interfering with Windows Security's functionality, preventing the app from starting.