How do I unprotect the wordsheet on my Excel 2007?

Hello techyv.com!
I have here a Laptop with an Operating System of Windows 7. I have been using Microsoft Excel 2007 for my work. Now I have been editing some stuffs with the project that I have been making, and suddenly I've realized that I have encoded a wrong password for it that is different from the usual that I have been using. Now I can't seem to remember what I have placed on it. May I ask how do I unprotect sheet on my Excel 2007?
