how can i change the settings so that when the other COMPUTER administrator changes my account back to limited account, that it requests my password to let him do it, for my conformation? i dont think this can be done, my bro takes it off and gives my account really annoying limited privalages that i cant do very much with, he puts it back to that, because i download i TUNES, and complains that all VIDS run in quick time on SITES, and his audio, runs in i tunes not media player, ive now clicked in the box to stop i tunes being the default media player, also with quick time, but i would really like some advice on how this can be done please? If you have full access, you can make your own account (or edit your bro's). This could help.You cannot restrict an Administrator's powers.  That's the point of being an Administrator.Ok look, u and ur big brother need to cordinate on this. If he is the Admin and not u its because hes older or the computer is his and in any case he knows better so listen to him and dont do what he dosent want u to do and then u wont need to secure ur account.
Its not possible to make him no be able to touch ur account, if hes the admin and ur just the limited account. He can disable ur password and do as he sees fit.
Making Itunes not the default video file program isnt the key. What u need to see is what files Itunes is associated with and then KNOCK off video files, of just right click - properties on the video file that u want to be run by another program and choose it, all files the same will run through that program from now on.