NFS:U problem with Inspiron 8500

[the xenon]

Hey
i finally got NFS:U its awesome best racing game i ever played, it runs pretty good (on high seetings) on my laptop Inspiron 8500 (pentium 4 2.5 and geforce4 4200)
the only problem happens when i try to turn on motion blur, it would work for one drag race but then when the race is over the screen turns black, but guages are still visible. Sometimes it happens in the middle of the race. Similar problem happens when i turn on road reflections on max, the road just turns black/see through.
EVery other option can be played on max with no problems
although i can play without blur and road reflections i am still wondering why if they work do they screw up after some time??
any help would be appreciated

thanks

[Codex]

You got the latest drivers? Didn't work with me either, the motion blur hurts my eyes after a while too though, so it's no big deal (does look nice on Drag though).

[TiGgErDbC]

After a while you will turn it off... or your nuts, i knowonce you hit about 120mph it starts getting bad, my cars do 170 average 200+ pretty easy(like 5 more races i'm done the game) after about 150-170 mph you cant see anything. trust me, light streak is cool but it blurs to much at higher speeds :)