Is my windows is 64 bit or 32 bit?

The answer that used to be here was essentially right at one time, but no longer is.

The simplest way to tell is to right-click your "My Computer" icon (depending on your version of Windows and your settings, this could be in your start menu, on the desktop, or in whatever insane place Windows 8 puts things; it might also just be "Computer" in the Start menu) and select "Properties."

Next look at the window that comes up. If it says "64-bit" somewhere, you're running a 64-bit version of Windows. If it says "32-bit", you're running a 32-bit version. If it doesn't say either of those things, it's almost certainly 32 (up to 2014, all 64-bit versions of Windows say they're 64-bit; 32-bit versions might or might not say they're 32-bit, depending on how old they are).