One of the issues I was having with the installation (even with patch 1.1) was that my c: drive didn't have enough available space to validate the installation. I wasn't about to delete or shuffle programs around to allow the install on my 18GB d: drive.
Having experience with registry edits here is what I did:
start, run, regedit
Hkey_Local_Machine/Software/Microsoft/Windows/CurrentVersion
Edited two values:
ProgramFilesDir
ProgramFilesPath
Originally the values were C:\Program Files but I changed it to D:\Program Files.
Reran the setup original program and the default location was on the D: drive, just the way I wanted it. Here is the advantage of this method over using the patch 1.1. The patch STILL requires enough drive space on C: but my method does not.
Change the registry entries back when you are done installing, and everything works fine.