First suggestion (although can't be sure its your HHD that causing the problem) make sure all your data in backed up to another device, and this includes all your settings, your e-mail address book, your favorites etc.
So far as the HHD is concerned, have you had any other symptoms i.e. failure to load your OS, noises from the Drive. Conversely, have you recently made any changes to your PC - software or hardware. Can you identify a specific action (loading or using a program or opening some hardware) that causes the crash or is it purely random?