You do not have to sell the securities in the IRA to convert to a Roth. Probably a good time to convert to Roth if you think the stock will appreciate significantly, but you also have to think about what rate the conversion income would be taxed at now, vs. future tax rate at which IRA distributions would otherwise be taxed when they have to come out of the regular IRA down the road.

In a regular IRA (or Roth for that matter) if you have a big loss in the account there is no tax hit, or benefit (deduction). If the entire account goes to zero there may be a possibility of a "miscellaneous" tax deduction if you itemize.