Black screen and flashing underscore windows 7

[Half23037]

A complicated story, it happened so I decided to try Linux and put it next to windows 10, I didn’t like Linux and I decided to remove it, But I didn't know what grub will remain in the Boot sector, after restarting the computer, I unsuspectingly turned it on, and it was there, it didn’t work to start Windows 10, it simply didn’t detect it, then I decided through ventoy make a flash drive, but when you start it with a black screen and flashing underscores, there was no such thing on the computer through Rufus.

[Steve2926]

Please explain clearly.
Why does this post mention windows 7 in the title but the post says windows 10?
Did you legacy boot or uefi boot?