Yea, checkdsk may take awhile. If it doesn't change for a couple hours though, then just restart.
Well the blue screen may not specifically mean the data on the drive is toast.
It can mean just one Windows driver file got corrupted or 1 bad sector on the hard drive and that is causing the issue.
You can pull off and save whatever data your friend needs while the disk is accessible in case things get worse.
If you are able to mark any bad sectors, reinstall of the OS may work; but you may feel more secure getting a new harddrive rather then dealing with an disk that has failed you once already.