If your mouse won't move or the keyboard doesn't work, the system is "blocked" by a software crash.
If waiting fails, try these keys in order:
If you suspect that your firewall or antivirus software is blocking certain programs or websites, try disabling them temporarily: how to unblock your computer
⚠️ Warning: Hard restarts can cause unsaved work to be lost. Use only when absolutely necessary.
When the screen is completely frozen and nothing works, you may need to force a shutdown: If your mouse won't move or the keyboard
If all else fails, you may need to reinstall your operating system:
If your browser is full-screen showing a loud warning claiming to be Microsoft, the FBI, or the Police, demanding money or a call to a phone number: When the screen is completely frozen and nothing
Since you visited a malicious site, run a scan using Windows Security (built-in) or a trusted free tool like Malwarebytes to ensure nothing dangerous was installed.