Why doesn't a file at the root of a drive work in folders?

Question

Task Schedulers

There is an exe file called youtube-dl, for ease of use, I placed it in the root of the disk. When you open it from a folder, it doesn't work, it says "youtube-dl is not an internal or external command, operable program or batch file", but if you open it in the "C:\" directory, then it works.
Same problem with ffmpeg. What to do?

Answer 1

Missing enter after last line

Answer 2

At a minimum, all paths must be explicitly specified (/whattotam/screen, /whattotam/php)

Answer 3

./youtube-d.exe

In the new assembly, updated in cmd

Answer 4

Why doesn't a file at the root of a drive work in folders?

Because it cannot be found.
Add the path to the file to the PATH environment variable, or run not by name, but by the full path.
Then it will work.