My PC turned off during formatting. What do I do?

I was formatting my PC because it was full of viruses, and out of nowhere it started raining. There was a thunderclap and suddenly the PC turned off. After a few hours, when the rain calmed down, I managed to turn the PC on. But now it seems that Windows got corrupted. It just shows a blue screen.

At the moment I can’t reinstall Windows again because I didn’t have it on a USB drive, I had used Windows’ own shortcut to format and install.

So now what? How do I run that program again to start the installation? I’ve already tried starting in safe mode, but it doesn’t work. It still shows an error. Help me, my God.