Style XP does NOT replace the UXTHEME.DLL file or any other files on your system, it merely patches it in memory as Chubs39 said. I use both Style XP and Windowblinds on my system, and they work fine if you know what to do. Always disable Style XP before applying a Windowblinds skin, and always unload Windowblinds before applying a skin with Style XP and you should be fine. I did notice though a few graphics problems, specifically buttons in some windows if you have both Style XP and Windowblinds installed, but then again, even with just Windowblinds installed those same problems occur, so it is not Style XP causing the problem (hint, hint). By buttons, I mean the buttons in the Display Properties Window using the button background color around the button itself or having a black frame around them. Always been a problem with that.
Now, I would not suggest however using WB 6 and Style XP on the same system, because WB 6 messes up a lot after an apply, titlebars disappear, etc. and it does not minimize to the system tray area as it should. Which means that since there is no "Unload" button in the program itself, the only thing you can do to fix your system is to uninstall WB 6.
