Take the following steps to establish if you have Windows 7 , 64bit or Windows 7 32bit operating system
Right click on Computer
Within this section it should say System Type and this will show if you have a 32bit machine or 64bit machine.
Alternatively, if you are using Windows XP, Windows 7 or Windows 8.
Press and hold the Windows key on the keyboard, then tap the Pause/Break key, then let go of the Windows key.