installing cs4 & uninstalling cs3 - problems!!

I recently installed cs3 on my Macbook from a DVD borrowed from my friend. It asked for the serials number, but (of course) since she is using that one herself the number wasn't valid. Still, the programs did run if i 'ignored' the system when asked to type the number.

I then decided to purchase cs4 student edition. Before installing it i dragged the cs3 programs into the trash can and emptied it.. stupid, i know now.

Anyway - i was wondering if anyone knows if this will cause problems in the future. Can i leave it just the way it is now, or should i somehow try to clean up the mess i made?
I found this link: http://www.adobe.com/support/contact/cs3clean.html
but it seems to be for trial versions of cs3, to be used before installing CS3 -- but of course cs3 is what i'm trying to get rid of!

Help!

 

Thanks!!