Ah, I just thought of an easy way to determine this ...

If you look on your C drive, do you see TWO Program Files folders, one named Program Files, and the other named Program Files (x86)?  If you see the x86 one, you have a 64-bit system and a 64 bit operating system, because the Program Files (x86) folder is used for 32-bit applications on a 64-bit system..