Shoutbox

first make 200% sure you've uninstalled SkinStudio completely and in the proper way! You didn't just delete the directory, did you?

Because, normaly these things will be removed if the uninstall is performed correctly.

First try to reinstall it and right after uninstall it...

If that fails (it shouldn't though), then you need to manipulate the registry yourself. Though, this can be dangerous if you're not familiar with it or if you don't know what you're doing...

Because it isn't a strait forward job (it depends on how SkinStudio added this to the registry) I suggest you to do the following:

1) Open the registry editor
2) Select the first registry map called HKEY_CLASSES_ROOT
3) Right click on it and choose "Export"
4) Enter a filename (eg: SkinStudioHKCR.reg)
5) Make sure that the "selected subkey" option is checked (default choose though) and then save the file to a directory of your choice.
6) ZIP the saved .reg file with winzip or winrar or something. (because the file can/will be very huge).
7) Attach the compressed file (zip or rar) to a post in this thread

I'll re-edit the file and attach a new registry file in this thread which you need to execute so the entry will be gone...