DELL OPTIPLEX GX280 WILL NOT RECOGNIZE USB MOUSE KEYBOARD

[carikamia]

checking on 2 dell gx-280. they both wont pick up the usb keyboard and mouse. note this pc does not have ps2 ports but it works fine other wise. please help. i need some serious answers.

 

[hang-the-9]

Reset the BIOS (unplug from wall power, pull the CMOS battery for about 15 seconds).