How do I find out what operating system I use? Should I install 32bit or 64bit version of TrueSuite / Protector Suite?

Generally, a computer's bit count indicates how much data it can process, the speed with which it can process the data, and the maximum memory capacity.

If you have 32bit version of Windows you should install 32bit version of TrueSuite / Protector Suite.
If you have 64bit version of Windows you should install 64bit version of TrueSuite / Protector Suite.

Windows Vista or Windows 7

If you have Windows Vista or Windows 7, there are two methods to determine whether you are running a 32-bit or a 64-bit version. If one does not work, try the other.

Method 1: View System window in Control Panel

1. Click Start, type system in the Start Search box, and then click system in the Programs list.
2. The operating system is displayed as follows:
   • For a 64-bit version operating system: 64-bit Operating System appears for the System type under System.
   • For a 32-bit version operating system: 32-bit Operating System appears for the System type under System.

Source: http://support.microsoft.com/kb/827218