64-bit op not working

[lenopro]

hello, i have recently purchased a lenovo thinkcentre m 3063 with 8gb ram, nvidia quadro fx 380 graphics card, intel core 2 duo cpu 3.00ghz. when i go into my system information it says 64-bit operating system but when i go into directx diagnostic tool and go onto the display tab it says current display mode 1280 x 960 (32-bit) (60hz). i downloaded a game and it only let me download 32 bit version. can anyone help me with this problem as it states that i can run 64 bit but it wont let me. how do i change it to 64 bit?
many thanks,
lenopro

[GastonJ]

You have a 64 bit computer and 64 bit O/S.
As for the display mode, that's the display mode, not the O/S.
What game is it? is there actually a 64 bit version of the game available, maybe not?