Running Windows 8 Dev. Preview on a Dell Latitude D610 (1.73Ghz, 2GB). System Hibernates fine (my main mode of powering off) but will not properly shutdown or restart. Every time I hit shutdown/restart it goes to a black screen. I know that it's still running because the power light is still on and the hard drive light flashes just as if it were still in use. I've let it sit for 3 hours in this state and it still refuses to shut down. Any ideas?

Backup any important documents, photos etc, try Refresh, if it doesn't solve it try Reset.
Reset Windows 8

After posting, I decided I would try cmd shutdown: shutdown /s /full. Worked. But I'm not sure yet if it will shutdown normally rather than through cmd prmpt. Thanks though, because I may need to reset to fix another problem: Windows 8 Network Connectivity Dialog Box won't come up

I was having a similar problem - My would not restart only shutdown so I reload W7 and had same problem, After that
I load XP and format the HD and then reload W7 and W8 with dual boot and is all good now.