My Apple Magic Mouse, connected to my Razer Blade (2014), randomly disconnects and won't reconnect. It's irritating, frustrating and makes me reconsider switching back to Mac. I knew it was almost certainly being cause by the sleep settings but I couldn't locate those. I found a support post when searching for "bluetooth mouse temporarily disconnects windows 8.1" that had these instructions:
Go to Control Panel
Go to More Settings
Search for BLUETOOTH and bluetooth options will appear under DEVICES AND PRINTERS
select CHANGE BLUETOOTH SETTINGS
Select the HARDWARE TAB
Select the GENERIC BLUETOOTH ADAPTER
Click the PROPERTIES Button
Click the CHANGE SETTINGS button
Select the POWER MANAGEMENT Tab
Uncheck the box that says "Allow the computer to turn off the device to save power"
and OK your way back out. (2)