I had a site a while ago which was a tutorials search engine, in 2002 I changed it to a training company, and a few weeks ago I changed it again to a tutorials search engine, the site is findtutorials.com The question is: why did the site loose its ranking and what can I do to fix it? right now it ranks first only for 'find tutorials' What about all other keywords? How soon can I expect it to gain ranking again? it has thousands of incoming links from educational and gov web sites.
try to submit your sitemap to SE's to update that your site has changed... it really depends on the keywords you were targeting.. if you have last targeted a keyword find tutorials, then changed to other keyword, then get back again to the first one,,, its possible that your rankings will go down... well thats just my humble opinion..
what were the other keywords you used to rank for ? If they are not relevant to your new contents its normal to lose the rank. what the text of your inbound links ? find tutorials ?
is there any backlinks loose for your site and have you made a big changes on your site before you loose your ranking?