TiBook 667 DVI crash on wakeup?

Greetings,
I've just got my hands on a 667 TiBook, refurbished it with a 160GB
Hitachi HD and 1 GB of RAM, and I am currently running OS 10.4.11.
Every now and then, upon wakeup from sleep, the machine will freeze.
This seems to me to happen more often when it´s running off of it´s
battery alone, but sometimes even with the ac plugged.
When i open the screen, it will light up, I can toggle between apps
(apple+tab) as well as move the mouse, but as soon as I attempt to
activate an apllication I can hear the HD spin up, and everything,
except the mouse will freeze. I´ve even had a frozen image of my
widgets halfway visible all over my screen. Is this some evidence of
some rusty hardware?

I sometimes experience the machine having difficulties with booting
up. Then the background will appear, but the dock will remain lurking
just below the area of the monitor. Coincidence? Hardly? Anyone with a
good idea out there?

Thomas