On latest version of Sublime, using Windows 7. This is what it's saying:

[WinError 2] The system cannot find the file specified
[cmd: ['py', '-u', 'C:\\Users\\Admin\\Desktop\\STR2LEET.py']]
[dir: C:\Users\Admin\Desktop]
[path: C:\Users\Admin\AppData\Local\Programs\Python\Python38;C:\Users\Admin\AppData\Local\Programs\Python\Python38;C:\Users\Admin\PATH]
[Finished]

Tried to change path, it is correct (I think)

I can run Python in cmd. Making a new build doesn't help, for some reason it just doesn't show up in Sublime (Tools>Build System).