Windows shows "raw" when it can't make sense of the filesystem. This happens due to filesystem corruption or to hardware failure. In my experience, the second is more often the case than the first -- and when that happens, only commercial data recovery services can repair the drive -- which tend to start at $1000 USD for any particular drive.
If you want to try using data recovery apps, a free one is "recuva". The best one I've used is Active@File Recovery Pro -- it's not free but the trial version will allow you to search the drive to see what it can find -- to see how well it works before you purchase it.