On CS3 (and CS4?) I had a really strange issue here at work. If I had set a certain network printer as my Default Printer in Windows then Photoshop would crash whenever I opened a second image in Photoshop. If I would just set any other printer as my Default Printer it would work as usual again. I found this solution on internet forums. So I'm not the only one. Everyone else at work has the same hardware and software, and the same issues.
Also with CS3 and CS4 I cannot drag-drop an image from FireFox into Photshop, however it works with IE.
Not sure if this helps, but it seems to be relevant to the topic.