I have ccleaner but its not set to clean automatically. Also I don't have to reboot for this to happen, I can be scrolling down through facebook and it will ask me to sign in again.
This also wouldn't explain my mount disconnecting.
Its looking more like I am going to have to do a complete reinstall to see if that will fix it, something I want to avoid due to the amount of astro progs and settings I have stored.
To be sure though I shall remove ccleaner and see if there is a difference.
Cheers, Rab.