Certain older 32-bit applications (notably Adobe Creative Suite CS2 apps, but there are probably others) object to being installed in “C:\Program Files (x86)\”, which is where 64-bit Windows wants to put legacy 32-bit apps.
The solution is easy but non-obvious, as is true so much of the time.
When these programs install and ask for an installation path, edit it. Change “C:\Program Files (x86)\whatever” to “C:\progra~2\whatever.”
This doesn’t work if you’ve disabled 8.3 filenames for performance, but that tweak breaks so many other things (including major antivirus programs, and even some Microsoft programs) that I stopped doing that tweak years ago. It’s just not worth it. Yes, I see the irony in me, of all people, saying a performance tweak isn’t worth doing.
So if you’re trying to avoid upgrading still-useful software to a current version at great expense, that’s the trick that often gets these programs running on a modern 64-bit system.
I can’t guarantee this works for anything but Adobe CS2 apps (I researched this when I mistakenly thought Adobe had released CS2 for free earlier this week), but it’s likely to work for other programs too, so it’s a useful trick to file away in case you ever need it.
Good to know. I’ve been in the habit of installing my programs to a separate drive anyway (at least those that will allow it) so I’ll be good to go when my new system arrives in the next week or so (moving from XP to Win7 Pro).