Bing ranks me normally. There are no spam measures taken against my site (I asked them). All urls stayed the same. It's been about 2 months
Have you registered with Google webmaster account? if no then do it now and verify your ownership.
Submit your website there and wait for couple of days, if Google crawler finding some issues with that sub folder; they will display there.
It happen some time when your website goes down; Google takes quick action to downgrade the rankings but once it is up again; it re-position those websites.
There are many reasons behind non-index problem in your website; if you can share your website url, it will be easier for us to share more insight.