Problems with installing office 2007 in windows 7

Hi

I just bought a laptop that has windows 7 and my friend gave me Office 2007 to install. When I open up the file there are are so many documents and so I clicked one of the ones that said "OfficeMUI"and the message comes up saying "This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package."

Can someone please explain what I am doing wrong?

Thanks