Sandra is correct, Baz, sorry, I forgot to mention that. The Firefox profile will be in C:\Documents and Settings\[user]\Application Data\Mozilla\Firefox (where [user] is 'Owner' in your case). The SeaMonkey profile will be in C:\Documents and Settings\[user]\Application Data\Mozilla\Profiles, and unless you've changed it, the folder should be named 'default'.
Please be aware, though, that it's not always wise to delete a profile, as there are occasionally some elements of them which can be 'shared' between browsers. Just make sure you have a backup of all your Firefox Bookmarks, passwords, etc, before deleting anything, and you should be OK.