Problems with my Mi2s & usb-debug

Nov 3, 2012
Hello to all, until a few days ago my Mi2s worked good.I wanted to upgrade the CWM but when I plug in the Mi2s to the PC does not recognize it more (unknown device), the battery is charged regularly. Another strange thing: I enabled the operator function with usb debugging, the buttons are active but do not have the icons on the top bar (connected to the PC and when it' detached). The smartphone is 'dual boot mode: Miui last rel- Cyano 19/07/2014.Il problem occurs on all 2 Rom. I installed drivers Xiaomi but nothing, could be a hardware problem?? MiniUSB port?Sorry 4 my bad English