We have a custom built PC running Windows 10 and it was operating flawlessly up until about five days ago. We changed nothing, downloaded only one piece of official software (from the Logitech website to support a new webcam), but the system suddenly started running slowly. The disk usage and/or CPU will randomly spike, even if we're only running one or two programs. Start running four or five and the performance lags significantly. We've run several anti-malware and system scans, have updated everything, tried a couple of fixes we found online (such as disabling Windows Search and superfetch), but nothing has worked so far. If anyone has any suggestions, we would greatly appreciate it!