Hi: I have a new Dell 1420 with Vista Premium. I use my notebook throughout the day (use it for an hour or two then leave for a meeting and return an hour later, ect). My old Inspiron 8200, which was running XP Pro, was always powered on and plugged in and running day and night. With my new setup (1420 running Vista Premium) should I keep it on day and night, shut it down each night, put into sleep mode, ect? Thank you!