I CAN'T DOWLOAD AND INSTAL MY ADOBE CS5.5

I have tried to install AE CS5.5 over the AE CS 5.0 and keep getting an Installation error.  The error wants me to reboot apparently because it thinks that is required to proceed.  Only I have rebooted 3 times and still I get the error.  Then it wants me to install Adobe ASA and to do that I am supposed to have AIR installed.  I have upgraded to AIR 3.5 and still nothing.  I am running Windows 7 Ultimate. What more do you need to know?  I have submitted the error package and there is no reply. There is nothing wrong with my AE CDs as they have installed before but the CS 5.5 is acting wonky.  Help is reall;y requested