My site was #5 on page 1 for a keyword with 1,635,702 results on MSN. Last weekend I dropped to page 5 ... just out of nowhere, and the site is slowing working back up, currently on page 3. What gives? Nothing changed on my end...
Very common for msn to put a new site,page up in the rankings than have it fall down shortly after. Be patient, update content pages.