Open Registry editor as Admin and locate:
Computer\HKEY_CURRENT_USER\Control Panel\Mouse
.
Scroll down the main pane until you find the “MouseSensitivity” entry and double-click it. In the “Value data” field, enter a number, with 1 representing the lowest speed, and 20 the highest.
Here you lower the value data and Press “OK".
Sometimes, third-party software can interfere with mouse functionality. Try starting Windows in Safe Mode and see if the double-clicking issue persists.