What's the *.* for?
It's a wildcard.
For example "*.png" would delete all png files in a given folder.
"file.*" would delete all files named "file" regardless of extension.
"*.*" deletes all files with a name and extension in a given folder.
If you were to do that in a command prompt, it would delete all files and folders in the "C:\Users\<user>" folder.