I am in the process of "cleaning up" an older computer that I have upstairs in my sewing room. I occasionally check emails (when working up there all day) or look up some youtube video, hunt for instructions or chat with my brother while he is working (works from home) and somehow this machine was horribly infected. Two trojan viruses, tons of adware and malware. There are 4 or 5 programs that I use to clean up a computer and it takes sometimes several days to run them over and over and I do so until ALL the programs come up "clean" (finding nothing to report). This is a real problem nowdays and I second the motion not to click on links from people you don't know... however, it also can be from someone you do know.... as they may have had their email address "hacked" and every contact in their address book will receive the malware/virus. Be safe out there, we are in a time when you can't be too careful.