I hate the spinning circle

If the spinning circle were like the XP hourglass, telling you a program is still booting up so you can't use it yet, that would be okay. I don't have anything against the circle itself, it's rather attractive.

But I'll be typing along and suddenly, the last few words I typed are not appearing. I click, and the screen either goes dark, or white (sort of cloudy, I can see the app but like through a thick fog) and the circle appears. If I resist the urge to throw the laptop out the window and wait, perhaps 30 seconds to a minute, everything comes back.

I WANT AN EXPLANATION. I don't like this stupid circle spinning around, giving no explanation as to what's causing this. I have 3 Gb of RAM. I usually have Firefox, Thunderbird and Open Office Writer open. And the windows Sidebar. And Norton running in the background. Not enough to make me run out of memory, is it? This stuff never happened in XP.