DiscSpeed 5 and PlexUtilities don't finish error scan

Hi, I seem to have a strange problem. When I do a disc quality scan with either of the mentioned tools, they don’t stop at the end. Rather, the progress shows 99% and the IDE light stays on. I can eject the disc, but the IDE light still stays on and the drive is not accessible in the drive manager anymore. Has anybody had this problem before? The board has an INTEL chipset, but the Microsoft SATA driver is installed. Windows 7 x64.