I just got my new mac pro today. It's a 2.8 Octo w/ an 8800 2gigs of ram and the 500gb WD that came with it. Everything was running great, I was surfing on the internet, setting up iphoto, copying over my music etc, when all of the sudden the music I was listening to stopped playing and I got a beach-ball. I don't know what happened--my finder stopped responding, I tried force quitting all my applications--but i couldn't regain control of the system. After waiting for a bit, I did a hard reset. My computer took a long five minutes to load, it was stuck booting on a blue screen no background, no nothing. Once it was finally booted I did another reboot to see if it was a one time thing...but it wasn't. Same problem as the first boot. I did the apple diagnostic test with the install dvd, and it took a whopping 13 minutes and 11 seconds (is that long?) it should only take 3 minutes right? The test came back saying there were no problems. I accidentally hit the start button again, and now it won't let me stop the test. ARgh, what's wrong with my new baby?!!! 
Update: first it freezes on the white screen before the apple, then it hangs on the grey apple with the white screen then it hangs on the light blue screen, and then it loads....
Update: first it freezes on the white screen before the apple, then it hangs on the grey apple with the white screen then it hangs on the light blue screen, and then it loads....