Windows 7 installation

I have a windows 7 disk but I lost the key.

The computer I want to install it on is a Compaq Pressario CQ60-419wm

I found this website: http://pcsupport.about.com/od/produc...dows-7-key.htm

and downloaded belarc advisor http://pcsupport.about.com/od/produc...pkeyfinder.htm

now how do I use this to get my key from the disk?

Thanks in advance