x200-15K resolution problem

hi everyone :

I have a Toshiba Satellite X200-15K and it's a brilliant piece of art !

I'm having problems with my screen resolution:

When i first bought the laptop it was all good , it came with windows Vista, and i was able to put 1440x900 as my desktop resolution. Later on , i bought Bioshock , the game , and just as most people who bought the game , i had problems running it . YES you're right , it's about that black screen that comes right after the Bioshock Logo. So, in order to fix the problem , i had to install the latest Nvidia driver for my laptop ( From Toshiba's website of course, since normal Nvidia drivers aren't compatible with it ). The game runs normally now , but since then , i couldn't find the 1440x900 screen resolution in my display settings.

I tried searching for new monitor drivers , but toshiba doesn't provide any special drivers for it . It's installed as a normal PnP generic monitor. I tried using Nvidia's control center , but there was no custom timing options in it. I then downloaded a program called Power Strip, yet again , i couldn't get the screen resolution 1440x900 although , i can put 1680x1050.

Does anyone have an idea on how to fix this problem ? My guess is that it can be fixed using windows registry , but the problem would be to know what strings to change in order to get the 1440x900 option.