I found my old Microsoft Wireless Notebook Presenter Mouse 8000 that I bought back in 2008. I lost the dongle however the bluetooth matched up easily with my Dell 6220 laptop and was working great.
However every now and then the connection was lost, requiring a visit to the Bluetooth control panel to ‘nudge’ it back into life. This was annoying to say the least.
The fix is not obvious however equally simple. Just find your laptop’s Bluetooth radio (likely a different name depending on your laptop) and click the ‘Power Management’ tab. Then just uncheck the ‘Allow the computer to turn off this device to save power’