Pls, i can not installFrontPage on my computer

I'm not sure what is the problem. Several things may apply:
1. It may doesn't let you install it if you don't have the apropriate activation key
2. Missing dependencies (such as .NET)
3. Was already installed and than deleted in whole or some parts of it.

I suggest installing a free alternative (maybe not so advanced and feature rich but will do the work when you get used to it):
1. NVU - http://www.net2.com/nvu/ check the screenshots and tutorial to get the basics
2. Or some other WISYWIG tool for web editing