This can occur if you install Photoshop AFTER applications such as Visual Studio, DreamWeaver, or <shudder> FrontPage. When setting up a new system, do yourself a favor, and be sure to install Photoshop prior to any ASP editors.
Here are some steps you can try to fix the problem:
- Go to Start, Run, type "regedit" without the quotes, and hit OK;
- expand HKEY_CLASSES_ROOT;
- find a folder named ".asp";
- right-click the folder and choose "delete" (back up your registry if you're not sure);
- close the registry editor;
- next time an asp page is double-clicked, you will get the "Choose a program to run this file" window. Choose the application that you would like to use to edit the code (e.g. Notepad or InterDev) and make sure that the check box on the bottom ("Always use this file...") is checked.
I have not verified these steps on Windows XP or Windows Server 2003. I do know, however, that Photoshop 7.0 and Photoshop CS (8.0) do not meddle with the .asp file extenstion any more, so this issue should be dying out.