What should I do on the laptop now?

Suddenly the screen changed and became so. I've turned it off and on again and it still looks that way. What is it and how will my laptop get back to normal?

Hard drive is defective or has come loose.

As can be seen on the screenshot, the PC can't find any boot medium.

maybe the hard drive broke

Do you have a USB to restore Windows?

If the laptop is older, it will most likely be the bio battery. I did last year. It can be easily accessible like mine. Unfortunately I had one with a cable where it is soldered on. I took a normal "Cr2032" button cell and freed the old button cell from the soldered cables and only bent the cables with needle-nosed pliers. Then the two cables are glued on from both sides with tape and then plugged in again (pay attention to polarity, take a photo beforehand). Then he was able to find the drive again because no drive or date can be found without a BIOS battery.

… Old bio battery

… New bio battery without damaged cables