Hey there, Bbale.
It could be, but unfortunately chances are really really slim if not gone for good. 🙁
The thing is that full format makes it pretty difficult for data to be recovered and additionally installing your OS has probably overwritten a lot of what was left, which makes things even worse. In my opinion, data recovery software might not do the trick, but you can at least give it a go: http://pcsupport.about.com/od/filerecovery/tp/free-file-recovery-programs.htm. However, please install the program on a different drive and use that different drive as the destination for the recovered data.
If you have no luck with any of the data recover tools, perhaps your best bet would be a professional solution, such as a data recovery...