After downloading from http www havit hk downloads, confirm that the driver was installed correctly.

Most Havit devices are plug-and-play—basic left-click, right-click, and typing functions work without additional drivers. However, to use macro keys, DPI settings, RGB profiles, or media keys, you must install the specific driver from the download center.

This is the most critical step. On Havit products, the model number is printed on a sticker underneath the device (e.g., HV-KB389L, HV-MS735, HV-H2002U). Match it to the list on the downloads page.