Alright guys.. whenever you post that it doesn't work, it would help if you posted some system specs as well.
For now, I think we have narrowed down the problem to Windows XP SP2 mainly on hardware that supports "Data execution prevention" (that being the newer processors). Unfortunately, I don't have the funds to actually purchase or do any testing on such newer hardware. However, I have had testers confirming that this works perfectly on Windows XP SP2 without hardware based DEP. So here's what I'd recommend you try to do...
1. Right click on My Computer, choose Properties
2. Look for the "Advanced" tab and click on it
3. Find the "Settings" button in the "Performance" section
4. Select the "Data Execution Prevention" tab.
5. Ensure that the first option is selected. If you want the second option to be selected, you can try adding NFSMW's speed.exe to the exception list.
6. Click on OK.. A reboot would be nice at this point.. Try the game again.
If it still does not work, select the second option, and add speed.exe to the exception list..
And if it still does not work... make a note of what it says on the bottom of that screen and post it here. It could either say "Your computer's processor does not support hardware based DEP", or it could say nothing at all meaning you have hardware based DEP. For more information, read this:
http://www.microsoft.com/technet/securi ... cnfxp.mspx
For the technical guys... Mod Loader requires write access to a non writable but executable page of the game. This is to perform some hooks that are used to redirect some calls and change the way the game functions. This only reason this was done was to ensure that you can use the mod without having any of your game files modified. This is accomplished by a custom "d3d9.dll" file placed in your MW directory. Renaming/removing the file will prevent Mod Loader from working, but your game will work just fine.