Read error while booting

The best way to check your hard disk for errors, is to download diagnose software from the hard disk vendor.

You can also install the program smartmontools and

1. Check the S.M.A.R.T. values of the disk using sudo smartctl -A /dev/sda (change /dev/sda to fit your hard disk),
2. Run a self test: sudo smartctl -t long /dev/sda (will take some time, you can check the status of the self test running sudo smartctl -l selftest /dev/sda).

If you mean I/O read error when reading from the harddisk then it probably is a hardware error. I would check the health of the drive (use smartmontools or Palimpsest Disk Utility).