FCP 5.0.4 still not working
I deleted the ID file, launched FCP, entered my serial number and once again the splash screen appeared and then vanished.
So it still doesn't work.
I'm not a happy camper at the moment.
Right now, I bet FCP isn't launching at all because something's wrong with your Final Cut Studio System ID file. It's in the ProApps folder. Delete that file (or rename it, adding "old" to the end of it if you like), launch FCP and enter your serials.
I deleted the ID file, launched FCP, entered my serial number and once again the splash screen appeared and then vanished.
So it still doesn't work.
I'm not a happy camper at the moment.