Solved! Go to Solution.
I solved this myself. The solution is to run setup.exe on the installation disk is Windows Vista compatibility mode.
I'm adding my own experience in installing LabVIEW 2009 onto Windows 7 (64 bit) in case it helps anyone else, but in fact there's no magic bullet for the problems I had, I did it the hard way.
I saw no error messages at all, just that when the installer wanted DVD no.2, the DVD drive seemed to disappear. Cursor remained as Windows 7 "timer donut", could do very little with PC except "master reset".
In the end I just copied the contents of the 3 install DVDs onto my hard disk. I named the directories as the DVD labels, and was impressed that the installer found all the parts automatically. Until it got to the Device Drivers DVD, which I had forgotten to copy, but mercifully at that stage I could browse to the DVD drive. No special compatibility settings used, but I did run setup.exe "as administrator".
I'll put this down as a Windows 7 bug (and maybe specific to my hardware ?) rather than an NI problem.
Along the way, as part of the sp1 upgrade, I got MS IE9, another great way to drop one's productivity (certainly made posting to this forum impossible, this done on a different machine).