If you are owner of multicore CPU and english version of NFS U2 there are two problems :
1. Game randomly hangs on loading screen
2. Game randomly crashes
Solution for first problem is no-cd/fixed .exe for french version instead of english one. Now it may seem a bit putting off but you will have to rename files in MOVIES folder from *_en.vp6 to *_fr.vp6 in order to see cutscenes. If you wont do it, in places of movies you will see just a black screen (it can be skipped).
Solution for second problem is disabling the game from running on multiple cores. As you may know it can be done through Task Manager but windows doesnt remember these settings so u would have to do it everytime you start this game. To deal with this download
CPU-control. Set mode to "Manual", run the game and alt+tab to this application, find SPEED2.EXE, right click on it -> "Add to selected CPU profil" -> "1 CPU" -> choose one of cores (if you will choose 3th or 4th core and u have only dualcore cpu there will be no effect). Go to options (lower right corner) and select "Autostart with windows".
I also used "WIDESCREEN CRASH FIX" from GameCopyWorld but I dont really know if it prevents any crashes, if you still experience them use it.
It took me a while to find solutions for these problems so I decided to share them with everyone who wants to play this excellent game.
Sorry for any mistakes in spelling/grammar.