fater upgrade to 10.4 the power manager stopped working, it would turn off the monitor but the power ramains on and when monitor turns off there is notification of noncompatibillity but striking mouse it will disappear

The power manager after upgrade stopped turning off the power - gnome offers switching off in 30 minutes and 1 hour and Xfce does not offer any options, previously it would show bar where I could choose switching off time by minutes. I'm trying enabling and disabling both but must be doing something wrong since nothing seems to be working. Do I have to downgrade back to 9.4 where it worked o.k.? Also update manager reports some repositories from CD drive missing does it mean that I have to burn new CD every time the system needs upgrade ? Thanks for any help with this, I am not a programmer just a user and don't remember all the commands needed in Terminal and with Terminal's help page am completely lost. I really need only that the machine would turn itself off at a particular time without me having it to turn off manually