i got a iomega 2TB external drive connected to my pc what uses windows 7 ultimate 64bit and while browsing or just doing standard task my external hard drive will decide to activate and makes sounds like its powering up for a mass transfer, this happens when serten directors on the main disk internal are opened and while this happens everything on the computer stops progressing , not like a freeze just like loading tabs will pause , progress bars will stop , everything will halt for the 10-20 seconds the external needs to do idk what , and then everything will continue,, why is this happening ? it happens like anywhere from every 30 to 120 minutes from each other through the day