Shares of SanDisk plummeted on Thursday after the company cut its first-quarter revenue forecast on lower-than-expected sales and lower prices. Jack Mohr, director of research for Action Alerts PLUS, says this is no surprise. Mohr, who's believed that SanDisk is in deep trouble for some time, believes the company is fundamentally eroding from a competitive standpoint. Mohr says not only has SanDisk lagged its competitors, but it lacks a proprietary edge to help it stand out from the pack and he's lost confidence in SanDisk's management. He stresses that a complete turnaround in SanDisk's business is necessary for the company to succeed in the future as well as a re-invigoration of its products.