First of all, is this a store bought copy? If it is, I would return it for an exchange. Also, if it's the 64 bit version and you are running the 32 bit version of windows, it may not work........or is it the other way around? With the cost of cs4, I would definitely return it for a refund or exchange. It is a great program, the best out there.......been using ps for years...good luck!
Here's the problem. I tried to install Photoshop CS4 everything went smoothly but when I opened Photoshop it crashed instantly. Then I tried to uninstall it and it had errors uninstalling and photoshop "parts" are still in program files also still in add/remove programs. When I try to uninstall again from add/remove nothing happens. I tried deleteing the folder then I got a message saying something (dont remeber) is being used and cannot be deleted. So I used a program to force delete the folders. Thinking when I reinstall that it would start fresh. Doesn't work, So I used another program to remove photoshop from add/remove + registry. Then tried to reinstall it finishes with errors. So I don't know what to do. Any ideas?
Thanks,
T-Virus

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic