My laptop suddenly freezes up when I do a full scan with MBAM or other security software, never going more than a half-hour or so before the entire system locks up. Oddly, quick-scan mode works fine. I can't help but think I've been infected by something that really, really doesn't want to get caught, but since I can't conduct any full scans, I'm not sure. I encounter the problem with MBAM and Avast (and even, out of desperation, Microsoft's Malicious Software Remover, which I never bothered to run as a scanner before). Scanning in safe mode doesn't help -- the exact same thing happens. I'm pretty certain it's not an issue of memory (I've monitored CPU usage during these scans) or hardware, and am thoroughly puzzled. Can anyone help? Thanks.