Just thought I'd mention that a friend of mine bought a tablet on my recommendation. He began having this problem shortly after flashing it. It was the browserd daemon; it didn't seem to be started properly when the system was powered up, or it was crashing in the startup process before the user ever got to the desktop.

I walked him through manually starting browserd, and it worked, but there were side effects of that...

He reflashed and the problem went away, too.

Quite a mystery.