Microsoft Bluetooth Keyboard 6000 Keeps Un-pairing Itself

Hi all, I really like this Microsoft Bluetooth Moblie 6000 Keyboard, but it continually un-pairs itself from my Windows 7 Home Premium rig. Each day, I have to remove it from the Devices Page, and reconnect it, which requires me to push & hold the small indent button for about 15 seconds and then wait for the rig to search for it, which happens quite quickly - then enter a new pairing...