If you’ve installed Dirty Pictures, restarted Photoshop, and still don’t see the plugin listed under the filter menu, then you’ll have to get your hands dirty a bit. All that’s required is copying a file to the Photoshop Scripts directory, but the location of those two things can vary based on your system configuration.

First, locate dirtypictures.jsx on your hard drive. In Windows, dirtypictures.jsx is located at %APPDATA%\Totally Rad Dirty Pictures\support.  You can either enter that into the address bar of Explorer, or navigate there yourself.  Typically, in Vista this will be c:\Users\<your user name\AppData\Roaming\Totally Rad Dirty Pictures\support (Which is hidden by default, thanks Microsoft!)   In XP, c:\Documents and Settings\<your user name>\Application Data\Totally Rad Dirty Pictures\support.

You can use THIS SCRIPT to open both the folder that contains dirtypictures.jsx, and the Photoshop Scripts folder. All you need to do is copy dirtypictures.jsx from one place to the other. To run the script, right click the link, and select “Save As”. Put the script somewhere you can find it (on your desktop, for instance). Open Photoshop, and head over to File -> Scripts. Navigate to where you saved the script and select it to run it.  Two explorer windows will pop up.  Copy dirtypictures.jsx from one to the other.

This little video shows you how to perform the manual copy in Windows