WebMatrix Says WP Installed But It Isn't

I have followed all the instructions to download & install WP, but it doesn’t work. I am using Windows 7 & have tried to install first with the MySql (didn’t work), then the SQL way (didn’t work). The WP download appears to work, but the installation never gets to the Dashboard point. It does ask for passwords etc. & the old website name that I assigned on my first try seems to be in the system (because when you click on the localhost URL in the WebMatrix console it goes to a ‘page’ with that name & boilerplate copy – no pics). I probably have a lot of unneccessary files on my system now (having installed & uninstalled so many things now trying to fix this problem), so perhaps this is the problem? Any help appreciated.