My Settings Keep Changing, help!!!

Ok, yesterday when i logged in to game, all my settings had changed to apparently the default settings??? (ie: an x by "goes afk when idle" etc.
Each time I log out and log in again, they change back to the default! And all my windows, ie, chat, my camera arrow window and my IM window goes back to being huge and in the wrong places from where I normally put them!
Can anyone tell me what the heck is causing this and how to fix it??? It's driving me nuts! Please be very specific as I am no computer wiz, thanks. (I have Windows XP Home Edition).
Thanks so very much!

My guess is that something is deleting your application data over in the c:\documents and settings\your username\application data\second life or the equivalent in whatever OS you are using. Do you have some kind of disk cleanup or disk optimizer that is running, or are you running SL from a batch file or from a flash drive? Does it happen immediately after you restart SL or does it happen overnight?

Anyways I see exactly what you describe when I manually delete the whole second life folder containing my profile information.