Not necessarily. I've seen controller and driver issues cause this in the past, along with a couple cases of deficient or low quality PSUs. Try downloading the set of drive diagnostics from your drive manufacturer. Install it to a floppy, reboot, and run the tests. Doing so will give you one of three results, an all clear, a failing drive, or a lockup. Provided the machine locks up I'd look at the controller or PSU.