I had this problem yesterday while trying to install Building Design Suite on my new laptop. The installation would hang in the initial dialog, same as yours. I killed the installation with Task Mgr and tried again, same thing. Killed it again and restarted the computer and tried again. This time I got to the add the serial number and product key page. The installation hung again but I got an error dialog stating that the Windows Installer had failed and hit OK to have Windows figure out what the problem was. Hit OK, nothing happened. Killed the installation again with TM and tried again. 4th time was the charm and the install completed. Not the most scientific of methods but I think that patience is called for. Just try and try again

The problem was the new antivirus software I installed, it was blocking it.
Thanks

glad that you got it sorted out!