The post linked above walks you through steps to recover data from a hard drive by repeatedly freezing it.  I haven't tried it, nor do I plan to. The best option, of course, is to have a backup so you don't need to resort to extreme measures to recover your data. Hard drives are cheap these days, and both Windows and Mac have built-in backup tools such as Time Machine. They're cheap insurance to make sure you don't wind up needing to freeze hard drives or perform voodoo rituals to get your data back.

One thing drive makers don't tell you is that as drive sizes increase (and density per platter increases), the statistical probability of a single-bit error on any given volume increases. So, as drives get bigger, the probability of failure increases unless additional steps (such as rigorous backup or error-correction) are taken.