Alt + F4 is another way to close a window.
If you want to remove the virus you can follow these steps.
1. Use Windows Restore to restore to a point in time before the infection.
2. If that doesn't work, disable system restore.
3. Download and install Malwarebytes (may need to download to a USB drive from a working computer)
4. Unplug network cable to prevent access to your computer from remote cracker.
5. Boot into Safe Mode by pressing F8 during boot up
6. Use Malwarebytes to scan computer for malware
7. Reboot to normal mode and run another scan.
8. If none of these methods work, remove the hard drive and place into an external hard drive enclosure, plug into a working computer that has up-to-date anti-malware and scan that infected drive.
9. Alternatively, if you don't want to spend the time scanning for viruses > back up data to external USB drive and then reinstall the operating system and applications.
