1. I never use paid Antivirus: It's not because that I can not afford them. But because I do not trust them. I believe free antivirus softwares are as powerful as the paid ones. Currently I am using Microsoft security essentials for my not "Genuine" windows 7 PC. 2. I never safely remove hardware: I do not go to the task bar, click a small removable disk icon over there and eject it safely. Or Some people do it more longer way, they double click it and they see a list of devices and they click stop working or something like that. But I just remove the device like pen drive and my camera or memory card. I don't know why I preferred this method, but I am always in hurry. 3. I rarely shutdown my computer properly. I just press the power button or remove the main power supple when I don't want to use my computer anymore.