In the last week, I've had a few calls from "Windows technical support" saying my computer (of which there are five in regular use, but they couldn't tell me that) has been sending them error messages related to corrupted files and malicious programs. Said files and programs are apparently "dangerous" to my OS and my HDD and could be/are damaging them. By this point, I'm skeptical but whatever - I hear them out and go through their instructions. They make me open up the event manager, see all these warnings and errors (mostly related to iScsiPrt - telling me that the iSCSI logong request had an error because the NAS isn't even switched on). They tell me this is all because of corrupted files and malicious programs. The first time I questioned them for a while asking what malicious file can cause me iSCSI errors, and a minute later he hung up in mid-conversation. The most recent time, after going through the same routine, he made me bring up the Prefetch folder, then told me that all the files I see there are corrupted and told me to delete them. Now I don't know that much about prefetcher, just that it pre-caches files to make Windows/programs load up faster. Just like ReadyBoost with flash drives. I know that all the files in the prefetch folder are temporary and can be removed without causing any problems to the computer (aside from making it slower to boot up next time until the prefetch folder is rebuilt). My question is, what could possibly be dangerous about the files in the prefetch folder? What could possibly damage my OS/HDD that Kaspersky, Windows Defender and MSE on various scanning schedules would not pick up? And also, is there any reason for me to spend another 5 minutes listening to them if they call again, or should I just tell them that they don't know what they're talking about and hang up?