Several "locally" PC builders may not connect every USB port cables.
Most PC nowadays have 2-4 ports in the back (on the motherboard) and
2-4 ports in the front. Without more details, noone here can really
tell you how many you are supposed to have.
Probably one 'extended' and 3 'standard'. That's the way
USB2 root hubs work. They appear as one USB2 root hub
(the 'extended') and as several USB1 root hubs (the
'standard' ones).