Aspect ratio fix!

I have 4:3 (VGA) monitor. When I chose 16:9 aspect ratio my image is stretch out! I tried to add black bars but it didn't work! Before I reinstalled my windows i had "GPU scaling" option but now I dont. I installed latest drivers for my graphics card but it does not have that option! I have old PC with "ATI radeon HD 3600"! Is there solution for this?      ...(sry for my bad english)