Juan is getting a strange data CRC error. Leo says that's likely a soft error, but it may also indicate a physical error on the hard drive itself. Soft errors are easy because he can always just format the hard drive and reinstall.
Leo recommends SpinRite, which can scan the hard drive, move the data, and mark bad sectors as unusable. Then, at least he'll buy some time for that hard drive. But Leo says that hard drives are so cheap, that once he gets the data off, he should just get a new one.