I installed Adobe CS3 on my mac (OS 10.6) couple months ago.

I removed it, however, every time I try to reinstall I am not allowed to put in a new serial because it seems my mac is using the ole one that I took off.

Is there a way to erase all of the information from an install? I want my system to be like Adobe CS3 was never installed so I can put on a clean install.

Thanks