Gail is correct and I didn't mean to imply that it was the cause of a row missing from an index.  I meant it only as a bit of advice and my out of place comment of "and then you won't have such problems" was directed at the too-wide an index problem and not the post I quoted.

I also forgot to add that I'd like to see the precise code that makes you think that an index is missing a row as well as the code that creates the index.  The reason being is just like Gail said.  Unless there's some sort of latent problem with the SQL Server code itself (and that HAS happened and will happen again) or you do have some faulty hardware, what you're describing is impossible and that's why I'd like to see the exact code you used to determine a row is missing from the index and the code that created the index so that we can try to duplicate the problem (although it may still be a problem because I don't have a copy of 2005 anymore).