If you have a google webmaster tools account, google will flat out tell you they have applied a manual penalty.
If you ask for a reinstatement review from google they will tell you if you have manual penalty.
But my 2cents, you don't have a manual penalty, you simply have a misunderstanding of current
SEO. It seems obvious to me that the latest run of the Panda program didn't like your site. The day Panda was last run you lost ranking. You can look up the dates Panda last ran.
Google says.. don't build links in an attempt to gain ranking.. and you have been.
Even footer links are viewed as an attempt to 'game' google's algo. (notice the footer links of myself and most of the other high ranking sites footer links.. Oh you don't see any... gee I wonder why?)
ANYTHING you do to try to artificially increase your ranking is BAD...
SEO methods that worked just one year ago... will kill your site now.
It's a new
SEO world and your playing by the old rules... your gonna lose.
All those links you exchanged/purchased/traded... need to be removed... That is the first step, then after you have 'cleaned up' you site, you can ask google for forgiveness for trying to game their algo and promise not to ever do it again and then you
might get some traffic from google...