Just for the search results, couldn't find a tested example, so here it is: if your windows crashes and your saved games are still in the \All Users\Application Data\NFS Underground directory:
1. start NFSU
2. create profile names with the same length of the profile you want to restore. Eg: you want to restore the user SERAPH, type HPARES (mirror)
3. close NFSU
4. open the Profiles.usr. Make sure you open it in a proper text editor (used UltraEdit myself).
5. just type your old userprofile over the new name: eg HPARES -> SERAPH.
6. save Profiles.usr
7. Game on!!!!!
Length of the usernames did the trick. Tried it with different lengths but game didn't accept it. You can see for yourself in UltraEdit... Anyways: game even crashes! Keeping the lengths of the usernames works fine for me
