Asus P8 Z77-V Pro motherboard
Win 7 64bit
I keep having issues with my mouse turning off for a moment, i thought it was the mouse but i believe its the USB ports. Today both my mouse and keyboard stopped working. Then i moved them to the front-side USB ports on the tower and they worked again. So its the rear ports having the issue, the ones directly mounted on the mother board.
Try turning off power management for ALL the USB Root Hubs in the Device Manager:
I.E. In Device Manager>USB root hub properties>Power management> untick the box that "allows the computer to turn off this device to save power"
I've found that with certain mobos, Windows has a habit of switching off USB ports to save power, whether or not anything is connected to them! This makes it seem like the keyboard/mouse or system has frozen up