help please

[macmininewby]

I bought aperture used. Loaded it entered the product # installed it on my mac mini dual core. Now it won't start up I get the error message failed to launch retry? It will not start. I rebooted, deleted and reinstalled, it doesn't help. What do I do?

[Dman77]

Did you uninstall and reinstall as per Apple's own guidelines here?

http://support.apple.com/kb/HT2945

Also, once uninstalled, maybe repair the disk permissions before reinstalling.

[macmininewby]

It turns out I hadn't removed it completely. and i didn't enter the serial number correctly. it is now up and running.
I appreciate your help