I bought a 2011 iMac a few months ago from an eBay recycler. My girlfriend and I instantly experienced an overall crap feeling when using it or just being in the same room; headaches, fatigue ect. We eventually considered it was allergies, though neither of us have any, so I opened it up, took an air can to it and kept it in the garage to air it out. Brought it back in a few days later and it didn't fix things. So I threw it back in the garage, got really busy, missed the return date and ended up buying another computer. Finally today I was working in there for the first time in a while and began to get a gnarly headache. I usually only get headaches from a missed caffeine break, so I drank a coffee but it still persisted and got a lot worse. I eventually remembered that I had this computer in there and now I'm seriously considering, as crazy as it sounds, that it's the hardware. Is that possible, or is it possible that they refurbished it with something?