To uninstall Adobe Photoshop cs3, you first need to try Add or Remove Programs utility in windows to remove Photoshop cs3 from your PC. But there are reasons like partial installation or damaged files that can be the cause the uninstaller to leave files or empty applications folders on your computer system after the removal is performed. You can perform the manual deletion of the files so that all the Adobe cs3 files will be removed and the system can be ready to install Adobe cs4.

Before doing this go to the folder options and show hidden files and folders. After this you have to deactivate the cs3 application. You can read the help file for more details about how to deactivate CS3. If the add or remove windows uninstaller utility does not worked then you can perform the manual removal of Adobe Photoshop CS3. The steps for the removal are:

• Backup all the files that you want to save from the following directories and then remove the listed folders and files
• Documents and Settings\\All Users\\Start Menu\\Programs\\Adobe Photoshop CS3
• Documents and Settings\\[User Name]\\Application Data\\Adobe\\Adobe Photoshop CS3\\Adobe Photoshop CS3 Settings
• Documents and Settings\\[User Name]\\Local Settings\\Application Data\\Adobe [any files and folders with CS3 in the name]
• Program Files\\Adobe\\Adobe Photoshop CS3
• Program Files\\Common Files\\Adobe\\Adobe Anchor Service
• Program Files\\Common Files\\Adobe\\Adobe Asset Services CS3
• Program Files\\Common Files\\Adobe\\Adobe PCD
• Program Files\\Common Files\\Adobe\\Adobe Version Cue CS3
• Program Files\\Common Files\\Adobe\\Bridge CS3 Extensions
• Program Files\\Common Files\\Adobe\\caps
• Program Files\\Common Files\\Adobe\\backup\\
• Program Files\\Common Files\\Adobe\\Installers\\8d0dc9390f2c596455e1446b5918a40
• Program Files\\Common Files\\Adobe\\Launch\\photoshop\\10.0
• Program Files\\Common Files\\Adobe\\Plug-Ins
• Program Files\\Common Files\\Adobe\\Startup Scripts CS3
• Program Files\\Common Files\\Adobe\\StartupScripts

After performing these files and folders deletion you need to remove the registry key of Adobe Photoshop CS3 so that it will be completely removed from your computer system. It is little risky to perform registry editing because one wrong step can cause the total system crash and so this thing is not for the beginners. But don\'t worry since there is third party uninstallation utility that are capable to perform all these kind of processes without any risk so that you can become free from the Adobe Photoshop cs3 for sure.