I think the common denominator here is Vista.

I'll go out on a limb here and say the easy solution is to take Vista out of the equation.
It works fine & OK on XP, so I would suggest to do exactly that.
It doesn't solve the problem, but removing Vista gets rid of the problem.

Photoshop was and is designed for professional use as the price tag implies. If Adobe can't or won't support PS CS2 on Vista, then the professional who prefers to use the older version must take steps to ensure he or she can carry on using the program that earns their crust. If this means reverting back to XP, so be it. If this means updating to CS3, also so be it.
The professionals can carry on using PS CS2 happily on XP and argue over the principles and ethics of a major software supplier allegedly using 'dirty marketing ploys' to enhance their profits.

This doesn't mean that 'ordinary' folk can't purchase the industry standard software, but they must research a product, any product, that costs a lot of money that can't be recouped from sales or products they produce. This means 'does it work and is it supported on my System'.