It wasn't clear in your post that the other workstations were W7. I assumed when you pointed out the failed machine was W7, you meant it was a difference between it and the successful workstations. I guess I shouldn't have assumed.
Did you actually run chksys.exe to see if the Crystal install completed on the first wksetup attempt or if it's still showing the previous version? It might not even be that Crystal is the issue. But for this upgrade, it seems to be the issue that pops up the most.
It is often extremely difficult to troubleshoot this type of issue over the forum, because there are so many variables that are being assumed.