What anyone thinks that this is a subject of miss use is completely wrong. I have posted this on the official site many times before Atari went down.
These are not registry keys and can be deleted with out consequences. A Re-Install can then be proceeded with out problems.
Keys can be found and "DELETED" for re-install are as follows;
WinXP and below:
C:\Documents and Settings\All Users\Application Data\Test Drive Unlimited\CDKey.txt - Game
C:\Documents and Settings\All Users\Application Data\Test Drive Unlimited\Addon.txt - MegaPack
WinVista and Above: Sorry I do not know. I don't have TDU installed on anything else other than WinXp.
P.S. These have nothing to do with Cracking, Hacking, or any of the sorts. These files only validate the installed item(Game, Addon).
These files WILL NOT UNINSTALL if you try to uninstall the game. So these files have to be searched for and deleted manually.
Have a nice day!
Quake