I tried Scott..And situation is like this:
Monitor native resolution is 1680x1050... so biggest resoultion you can set in game is 1366 x768...And if you have that resolution set in windowed mode it is window in midle of screen...Now i run "the tool" and setting 1600x900 in it, and only thing it does is that it stretches that window which becomes blurry ,cause resolution actually doesnt change but the size of window