[G5] Strange behavior

[Dick Grable]

My G5 1.8 GHz SP has been acting strangely lately. Somewhere along the
upgrades to 10.4.x the shut down and restart options (along with
control-eject bringing up the power-down options) quit working. Now if a
software install requires a restart it has to be done manually. This is not
a problem with 10.3.9 only 10.4.x. And even stranger the upgrade DVD no
longer works as it can't seem to find any drives with a previous 10.3
install (there are at least 4 including an external f/w). Since this all
works fine on my new Powerbook am beginning to suspect a hardware problem of
some sort. Thank goodness for AppleCare.

Any ideas out there?