I have a MacBook Pro that recently started making a zipping/whooshing sound (much like when I send off mail) shortly after my desktop is up and running. It was not happening previously. It sounds and acts very much like a virus/malware that I had on my PC laptop once. The closest change that I can trace it back to was when I plugged in my external hard drive to search for some files. This external drive has previously been plugged into other computers (all Windows driven) that may or may not have been infected at one time. I downloaded the ClamXav and ran it a couple of times. It picked up a couple of phishing emails that I promptly deleted, but the sound continues. I'm new to Mac so I'm not too familiar with the system structure and don't really know what's suspicious in the Activity Monitor. Has anyone ever experienced this? And if it's not normal (which I obviously suspect it isn't) what should I do to fix it? Thank you for your help.