hmm.. never noticed it dave, running ccleaner before shutdown, and winpatrol in startup. if you still have an issue after that, regedit would seem to only option to prevent files from loading..
well, that`s a bit beyond me dave.. doing things programatically..never found my feet there, not for want of trying.. but being a wicked lazy old man, i would be tempted to put a line into the good old autoexec.bat file.. like @echo y|del [directorypath] uxtheme.dll should load before windows and kill the darned thing.. unless it is read-only. [back it up elsewhere at shutdown first..]
http://msdn.microsoft.com/en-us/library/windows/desktop/aa365240(v=vs.85).aspx MOVEFILE_DELAY_UNTIL_REBOOT Rename the original file Add your replacement file Check it exists (AV didn't block the action) Mark the renamed original file for deletion or restore it depending on the result