For the last couple of weeks or so, when doing random surfing on the 'net (i.e. no significant CPU usage like watching a video), my machine's fan turns on at full speed and it keeps running. This makes me think there may be some spyware/malware which occasionally wakes up and does something. My machine never did this before, hence the suspicion. Normally the fan only comes on when I'm watching videos. I forgot to run "top" so I can't tell what the significant processes running were, but I think I will do that next time. However, is my concern justified? Do you folks use an tools to check for spyware/malware/viruses? Thanks.