What is the Difference between C:\Program Files and C:\Program Files (x86) in Windows 7?

You have the 64 bit and 32 bit OS in your computer, the good one, can use 64 or 32 bit programs.

64 bit installs to C:\Program Files and 32 bit to C:\Program Files (x86)

Those programs that are installed in the Program FIles (x86) folder are 32-bit programs while the ones installed in the Program Files are 64-bits. You only get these two folders if you have a 64-bit OS.

If you only have a 32-bit OS then programs will be placed in the Program Files folder. It doesn't need to have an (x86) label as there is no need to. There won't be any other folder created by the OS.

In 64 bit windows the 64 bit programs are instaled to C:\Progam files and the 32 bit programs install to C:\Program Files (x86).

The x86 one stores 32bit programs and the normal one stores 64bit programs. This allows a computer with a 64bit os to take advantage of 64bit programs while still being compatible with 32bit programs.