When you say remove, you mean delete, right?
Yes. Remove, delete, erase, however you want to call it
I don't need to keep anything. So I can delete just the entire folder in which I installed ownCloud?
Did the php setup file install any files elsewhere?
Files, not as far as I know - except if you specified a different data directory (have never used the web installer myself, but if it's anything like the "normal" setup routine, you would be able to specify a data directory of your choosing, which also would be created).
The database of course is not really a file and would need to be taken care of separately as mentioned in my above post.
By the way, sorry to see you leave
. Anything specific which turned you down? If it was the "bugginess" of the 5.0.0/1/2 releases, you might want to try either the 4.5.8 or 5.0.3 releases, they contain considerably less bugs...