:If your motherboard has two PS2 ports, just connect the PS2 mouse to the green PS2 port, and then the PS2 mouse can be used.
If your motherboard only has one PS2 port, please set "PS2 Y-cable” to "Enabled”. Please press "F2” or "Del” during POST to enter BIOS, select the "Advanced” menu, "Super IO Configuration”, and set the "PS2 Y-cable” option to "Enabled”. Press "F10” to save the configuration. Then the PS2 mouse can be used.