Stuck on grey screen after boot, Disk Utility says HD is OK

"You'll need to boot under your recover DVD in order to run disk utility again from the DVD to fix the boot sectors and any format corruptions.

Do you have a good backup? if not get an external HD of equal or bigger size than your internal (firewire is best) and after booting from the DVD you should be able to copy your current files from your HD over to the external HD (do a full copy by dragging the HD icon over to the external HD). Once your backup'ed you could try reformatting the internal HD and then install a new copy of OS-X on the HD then copy back your files using the migration tool to restore from the external HD backup.

Don't forget to run 'Software Update' before recovering your files so all of the security updates are on your system first. As of late Mac has been hit with some malware attacks, it's now time to start being more aggressive running anti-virus (malware) software. Make sure you are and your files are OK.

At this point you should be OK

You still may have problems with Chrome after restoring as it appears it's files are corrupted. Delete the App library files under the user account and you may also need to re-install the app it's self.

I would recommend creating a few different user accounts, use one everyday and one just in case (admin) just make sure this one has a password that you won't forget. Use this admin account when you get into trouble."