MacBook Pro stuck on grey screen with Apple logo and spinning wheel The only thing it will let me do is booting to Safe Mode. After running /sbin/fsck_hfs -drfy /dev/disk0s2 it returned with an incorrect number of extended attributes (it should be 486802 instead of 486801) and disk0s2: i/o error. **the volume macintosh could not be verified completely.**

Running the command once more it returns:   

**the volume macintosh could not be verified completely.**
volume check failed with error 5
volume type is pure HFS+
primary MDB is at block 0 0x00
alternate MDB is at block 0 0x00
primary VHB is at block 2 0x02
alternate VHB is at block 623463230 0x25294b3e
sector size = 512 0x200
volumeObject flags = 0x07
total sectors for volume = 623463232 0x25294b40
total sectors for embedded volume - 0 0x00
checkHFS returned 5, fsmodified = 1
*****the volume was modified *****
doing update / reload mount for / now
:/root#

sw_vers: Mac OS X 10.9.5


I don't know what to do now. I really am trying to do this myself without spending any money or as little as possible. And I cannot do anything that will wipe out all of the info that is on it.
I/O errors are usually bad news- often a sign of failing hardware. :(

If you don't have a backup already be sure to make one ASAP. For example, try booting in target disk mode (hold the T key while starting up) and connecting to another Mac. From there make a copy and try running Disk Utility to repair the volume.