i finally fixed it.

i dl'ed shellon3 and set that as shell just to see what would happen the result of which is that on bootup i was presented with two instances of shellon.

that confirmed though that the problem wasn't litestep and after poring through the registry i noticed that a backup of userinit.exe i had made while messing about with reshack and logonui had somehow crept into the registry.

userinit is the program that calls for the shell to load so two instances equals two calls for the shell.

i dunno if anyone else is likely to play about with that file (i have no idea why i ever messed with it) but if anyone gets similar problems then its worth investigating in that area.

bear in mid that you have to be very careful with userinit because without it you cant login to windows and so if you do anything make sure that you leave a backup copy so as you can easily replace it from the repair console if things go wrong.

thanks for the help jugg