Did Tech Support offer the option of WebExing into your computer to check it out directly? The reason I say that is this is often the best way of fixing tricky install problems. I had a similar problem myself recently and SAS Tech Support pretty much spotted the problem straight away after WebExing in because they know what to look for. I suggest you ask them to do this as they have drawn a blank so far.
On the community we are flying blind on your problem because we don't know all of the circumstances that have led up to your problem. We can only give you our best guesses.
At what point did the install process fail? It sounds like you were able to select 64-bit SAS 9.4 (??) for installation - what happened after that? Also there must be something different about the installs on your colleagues PCs that worked. Is there another PC around to try a test install on as this might help you pinpoint where yours is failing.