that is what I was suspecting.
What this means is that your hard drive may have failed, because it is not being recognized even with a command-line tool like fsck, which almost always provide access, even if the hard drive is not functioning in any normal boot up capacity.
In the case of a hard drive failure, however, the flashing folder is an example no activity coming from either a failed Mac OS X volume, or worse yet, a bad hard drive.
I believe it would be best for you to take your Macbook Pro in for service to your local Apple Retail Store Genius bar or Apple-authorized service center and at least have a diagnostics performed on your Macbook Pro.
I have seen this issue too often and a flashing folder on your Macbook Pro, needs to be diagnosed by a certified Mac technician, especially because these models contain some of the most sensitive components.
Just for your reference, I have taken the liberty to provide the store locator links to your local Apple Retail store as well as a general store locator for locating any local Apple Authorized Service center in your area.Apple Retail Store
(Genius bar) Apple Authorized Service Provider
Please let me know if you have any more questions, I will definitely be glad to answer them for you, but I will also add that this is my best answer, given the symptoms of your Macbook Pro issue.
Thanks for your patience!