How to remove Pro sites completely

After failed to get support for integrating Paypal express checkout, I wanted to remove Pro sites completely and re-install it.
I tried the following :-
1. Network Deactivated
2. Deleted
3. From phpMyAdmin I removed the tables it created:
Now the problem is,
When I again upload,network activate it..The settings saved for the previous installation(the one I removed before) appears. All the settings are pre-selected as used to be in old one.

Please guide me to remove and install Pro sites freshly.