Dell will not fix it themselves. Dell just verifies the failure remotely and sends you a new hard drive to install yourself. It should be a hard drive with windows and all the original software already installed. You return the failed hard drive in the same box. Dell usually asks for a credit card in case you don't return the failed one. 
I have a Dell Inspiron 15, I believe the model is I15RVT-3809BLK.  The hard drive has failed.  On startup the message is something about media failed, and when booting to diagnostics the HDD test states that no hardrive is installed, or something close to that.  All other diagnostics test good.  I actually took out and reseated the hard drive and rechecked, still the same problem.  So, I'm pretty sure the HDD is no good.  This is my daughters laptop, so nothing real essential is worth the cost of recovery of data. My dilemma is this. This is still under Dell warranty period, but I would rather purchase a new HDD without having to wait forever for the warranty service. I can replace the HDD myself, done this many times. But this laptop doesn't have an optical drive, and the Windows 8 software is preinstalled, and there is no product key provided from Dell.  So HOW do I reinstall Windows 8 when I replace the defective drive? I basically need a USB stick with the software.  This should be available for free since I'm just fixing a bad Dell HDD.  Can anyone help me with how I go about this? Thanks!
Inspiron HDD fail