As I've had two email questions this week that both touched on this, let me clarify:

Microsoft Office (Word+Excel+Powerpoint) is a commercial product and has never been "free on the internet". It has also never been a part of Windows. It might have come with your computer but that's the manufacturer (Dell/HP/etc) including it in the package. Think of it like whitewall tires -- they are not standard on any car but the dealer might throw them in to sweeten the deal.

There are some free Office-compatible softwares, most notably LibreOffice and OpenOffice. I favour LibreOffice as it get updated more often and will open a few more obscure file types.

http://www.libreoffice.org/