the easiest way to find you key for most games that doesn't require any extra cash or third party programs is to go:

Start\Run...\regedit\HKEY_LOCAL_MACHINE\SOFTWARE\Electronic Arts\EA Games\Burnout(TM) Paradise The Ultimate Box\ergc

or

Start\Run...\regedit\HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Electronic Arts\EA Games\Burnout(TM) Paradise The Ultimate Box\ergc

if you have a 64bit OS

the item with the Name (Default) is your key its listed under the Data column

but that only applies if you have the game installed

I have the same problem with GTA IV I run the game for 30 seconds and then the world just vanishes.

I have a 3870, Catalyst 9.1 and the latest DirectX, it only has happened recently though probably 3 weeks ago.

It also will make the world vanish if I goto the menu. I'm thinking it might be a hard drive problem because it started when one of my friends was copying some files from my computer.