Depending on the SMART error, the drive may be dying and need replaced. You can try running a chkdsk on it, but can't guarantee results since the drive status is unknown. A program like speedfan or hdtune can read the smart values.http://en.wikipedia.org/wiki/S.M.A.R.T.#Known_ATA_S.M.A.R.T._attributes
Open a command prompt and type:
chkdsk c: /f /r
This can take some time to run so be patient. if it asks to run at next boot, say yes, then reboot.