It's been a few weeks since I've done a scan, and last night when I went to plug my 360 controller into one of my front USB ports, my computer restarted on its own. When it came back up, it said Windows had restored from a serious error. I tried to run Scandisk at this point (using the method I always have in the past -- selecting Properties on the drive, Tools, Scandisk, and checking both options), but it said it couldn't run Scandisk. I'm not sure if the reason is related to the "serious error" that occurred, but I sure don't want to lose my ability to do periodical scans. I scanned for viruses/malware last night, using both McAfee and Malwarebytes, but neither program detected anything. Not sure how to proceed at this point.