32bit or 64bit?

To find out if your computer is running a 32-bit or 64-bit version of Windows in Windows 7 or Windows Vista, do the following:

1. Open System by clicking the Start button, right-clicking Computer, and then clicking Properties.
2. Under System, you can view the system type.

If your computer is running Windows XP, do the following:

1. Click Start.
2. Right-click My Computer, and then click Properties.
   • If you don't see "x64 Edition" listed, then you're running the 32-bit version of Windows XP.
   • If "x64 Edition" is listed under System, you're running the 64-bit version of Windows XP.