If you are asking on how to determine if your computer is running on 64bit or 32bit, then the easiest known way is to simply Right Click on 'My Computer' > Properties
And you will find something like this:
Or Control Panel > All Control Panel Items > System
This really defers from computer to computer and what OS you are running but the info should be on Control Panel under "System".
Yeah! I know my pc specs ain't that good and I am still running 32bit :)