site disappeared Overnight wrt Rankings in Google

[markov]

Till August 13th, i did had a decent SERP in Google, but the next day morning all of the sites disappeared from the top places. No where in the top 20. The Keyword which has very low competition was in the 1st position earlier. But today, even that disappeared from the rankings. Even the blog results disappeared overnight. What could be the reason?

Does the web hosting has any role in this? Say if the google crawls the site when the sever was down for maintenance reasons, will it cause this sort of adverse effect?

That was the issue when Google Webmaster tool reported that the site has been crawled on Aug8. But today when i checked out the same, the last crawled date was on Aug13. Interestingly from Aug13th onwards, I'm facing this problem.

Last week may be on Aug6th or so ... i've changed the images in my site to noadware-free-anti-spyware-download-graphic.jpg from noadware.jpg

Is this anything to do with the fall of SERP? Except this change i've nothing added or deleted.

Please help me in this regard. Thanx in advance.

[ben_tambling]

Is this anything to do with the fall of SERP? Except this change i've nothing added or deleted.

Please help me in this regard. Thanx in advance.

are you promoting and building links to your site? do you link exchange with other sites?

[markov]

I'm promoting my site well. I used to exchange links, but i'm not doing it now.

[luxury_homes_]

Last week may be on Aug6th or so ... i've changed the images in my site to noadware-free-anti-spyware-download-graphic.jpg from noadware.jpg

I am not sure but I think this changing name of image could be the reason something like over optimization or optimizing for search engines rather than considering visitors for drop in SERPs some times it's not allowed to do.

[ben_tambling]

i think alans has the point.. maybe the over-optimization gave you bad impressions in SEs... also check if you link some sites that is banned...

[Adan]

How old is your site?