Then you need to apply another fix to your game. I am providing you steps, follow them and see if the problem is resolved.
1. Go to "http://thirteenag.github.io/widescreen_fixes_pack#nfsmw" and download the widescreen fix for NFS Most Wanted.
2. Now, extract it and you will find the following files:
dinput8.dll and a folder named "scripts".
3, Copy dinput8.dll, nfsmw_res and NFSMW2005_widescreen_fix.asi to your installation directory.
Run the game and see if the problem gets resolved.
This method uses registry editing trick, so carefully follow all the steps and do not change the things unnecessarily or unknowingly.
Follow these steps:
1. Open Run or press Windows key and R together to get the same.
2. Now, Expand HKEY_LOCAL_MACHINE, after this expand SYSTEM.
3. Now expand ControlSet001 and then expand Control which will open up a huge list.
4. Now scroll down till you see the folder by the name "GraphicsDrivers" and then expand it.
5. You will see a folder "Configuration", this is actually the configuration for your graphics driver and hence a property of your graphic card.
6. Just expand it and you will be provided with a folder (name can be different for different users). Just expand it and you will be provided with another folder named "00". Expand it and you will finally reach the main configuration folder "00". Click it and you will see certain files at the right hand side.
7. Search for "scaling", and change its value to 3, keeping the base "hexadecimal".
Note: If you find more than 1 folder in Step-6, then you will have to change scaling for each of these folder to 3.
8. Exit the registry editor and run your game and see if the problem gets resolved.
Note: With this method, we are changing the property of our graphic card, so every time you run any app which is not opening in its native screen resolution, then the graphic card will force that app to run in your screen resolution. So, there's no harm in this method.