If you can't disable from BIOS, then boot windows up: goto start:settings:control panel:double click system:tab at top says 'hardware' then click 'Device Manager': Then scroll to bottom where it reads 'universal serial bus': click the plus to the left of universal serial bus which displays all the USB devices: right click each one of them and select 'disable
This will disable USB ports from windows. But anyone tech savvy can undo this. Try turning USB ports off in BIOS first then set a BIOS password. This will ensure no one can just go back and 're'-enable the ports
Bria