I upgraded to 12.04 a couple of days ago and it was running fine.

But this AM I started it up and it's a DOG. It's so slow even the mouse is unresponsive.

There seems to be a lot of disk activity even though the machine is just sitting there.

I did run some updates yesterday but the system was OK after that. Otherwise, I've changed nothing.

And I can't load any applications like System Monitor to try to see what's going on. Or maybe System Monitor will actually load in a day or two. It's really that slow!

What's going on? And what can I do?

I'm desperate.