having issues with my g4 laptop and leopard

[Turelim]

I have a 17" G4 powerbook laptop and have just installed leopard it's upgraded to 10.5.2, I play world of warcraft a lot and have never had any real issues but since upgrading the OS i sometimes get the sleep, cancel, shut down, restart window up like I've used the power button but I haven't. Has anyone had the same problem or hear of similar and may know of a mix because it's getting to the point where I'll have to reinstall the older OS.