If you have a genuine serial key for Ae CS4, try to enter it again and hit next to serialize the product and check if that helps.
Simply input the serial again and see if it sticks. If it doesn't, then you need to check things like permission issues or firewalls and virus scanners blocking things. Also check the stuff explained here. if you get a warning that your serial is invalid, contact costumer support.
Move the cache.db file on the desktop ,
from this location :- Program Files\Common Files\Adobe\Adobe PCD\cache
and then re-open yor application and put in the serial number
The serial did not work when I put it in. It says 'invalid.' When I pressed quit on the loading screen pictured on the original post, AE started up like usual. It didn't have any sign that it was a trial either. I'm really confused at this point.
You should receive the dialog if you are running in trial mode each time you launch the application. Also looking at this thread it appears you used a registry cleaner and then a restore point but I don't see that you have tried reinstalling the software? Have you tried removing and reinstalling the software?
Also as a tip before using any type of registry cleaner I would recommend always going into Regedit and backing up your registry. This way if the registry cleaner does do damage you can restore the damage which was done.
Reinstalling the software did it! Thanks!