I think I have tried all combinations. I started with Archicad 64 since I have a 64 bit system, when that didn't work I uninstalled it and tried Archicad 32, when that didn't work I posted my problem in this forum, you responded and I tried your fix list on Archicad 32 (since it was installed) as mentioned previously one of the steps erased the Archicad32 system files in c:\Programs(86) directory. I reinstalled Archicad64 applied your fixes still no luck. Archicad 64 still does not recognize Quicktime Pro, which I have had installed for many years and kept updated.
I am not a nubie with computers, I have been building them since 1976 and subscribe to Microsoft Technet and have installed Windows 7 over over 2 dozen times. I have never had this much problem (nor patience) installing software.
I hope Graphisoft can improve the installation process so if the install fails it can do better than an incorrect cryptic error message.
I am intrigued as to why I have having this problem. Others have got Archicad to install and operate normally but there seems to be some conflict on my system, that Archicad does not like. I may have to try it on another system, when I can find the time & the system.
Does Archicad work on a virtual machine?