Mac equivalent of blue screen of death?

So i recently updated osx to 10.5.4 i believe it is? Ever since then i randomly get a grayed over screen and a message that says i have to restart my computer. Before this, finder was crashing, but it hasn't happened in awhile. It seemed to happen whenever adobe flash player 9 loaded and some kind of script messed everything up. (even though i run noscript with firefox)

I am running leopard on a powerbook titanium, 1 ghz, and yes, that is ballsy but i haven't had any problems before.

Someone please help!