Have you accidentally deleted files? Does your system crash saying "INACCESSIBLE_BOOT_DEVICE"? Not sure what to do? STOP USING THE HARD DRIVE IMMEDIATELY! The more it's used, the more damaged/overwritten it may become. If you're currently using the computer you need help with, quickly write this number down: 763-381-4064. Then unplug the computer's power cable - don't even shut down.