Samsung HM120JC hanging on boot up and when plugged

I have a Samsung HM120JC outer HDD, it has 120GB, so it has no need seperate electric port, like hdd over 250GB need. It went normally for few months, great speed and everything. But know when i plug it in USB it tells me “this USB can go faster with USB 2.0” – thats normal, but then it just hangs. If i try to access it through Explorer, it hangs the explorer too. I know it’s not a virus, because i tried to scan it with “USB Virus Scan”.