Most Wanted Races Freeze

can you give more information ? like pc specs and OS ?

I remember I'm having this issue also when I still have a weak PC when I was playing most wanted before. My main suspect for it is that it's the Video card ram/speed is too low (My hunch is freezes happens when it swap, re-cache and load the texture for a split second)

When I upgraded my vid card, the freezing virtually disappeared

Have you checked the temp? If not, check`m with HWMonitor and leave a feedback. link

Lets just say it worked fine for the first few races I did, but after that, they just stopped working.