Does anyone know a way to reuse old save games in Dirt? I've passed almost 3/4 of the game, when I needed a reinstall; I tried to copy old saves to the savegame directory located in C:\Users..., but game always informs, that savegame is broken.
This is a very, very old problem with Codemasters' racing games. Sometimes they will become corrupted for absolutely no reason, and they're difficult to recover because they're stored in an encrypted format, to prevent tampering. Because it would impair the user experience if people could cheat in the single-player portion of the game, obviously!
Anyway, there is no tried-and-true solution that I've ever heard of. Here'a thread where a bunch of people report that making random changes to their settings fixes the problem with F1 2012.
Here's a thread about it happening in Dirt 3, only it was not precipitated by trying to move the files to a new installation. There's no answer suggested, though.
You can find threads like this on gaming forums everywhere, and there's never really a solution.
If you bought a code for DiRT from Codemasters, and are having problems after a reinstall, I'd suggest you check the DiRT forums, or email Codemasters at email@example.com.
Any other method of acquiring new codes is likely illegal, or a violation of the game's EULA or Terms of Service.