Robots.txt and the Google sandbox

Does de-indexing put one back into the sandbox?

[Rollo]

I have a site that's three years old and it's been experiencing some Google strangeness with PR. Recently, Google PR0'd all pages except the homepage. I was wondering if I blocked Googlebot for a few months to get a clean start, if that might plunge the site into the sandbox, again?

[webkid_san]

This normally happens if the other pages have duplicate content ...