I had a drive that was not being detected by SpinRite. I would get to the first page, select level 4 and hit enter. The next screen says something to the effect of "discovering mass storage devices" and it would just stay there and never find the hard drive.
I rebooted, went into the BIOS and changed the SATA configuration to ATA instead of AHCI.
This solved the problem and SpinRite is running happily now. I am also getting SMART data in SpinRite as well.