If your computer admin has disabled your computer for using USB port, you can easily enable USB port of computer for using your pen drive.
There are two method for it
1. If you know admin password, login with it and just go at My computer > right click > Hardware> Device Manager> click on plus sign of Universal serials bus controllers > right click on each USB drive and enable all one by one..
2. If your PC admin disabled USB port through BIOS setting and you don’t know admin password, just do some risky work.
Off your computer, remove the power cable. After that open the chassis of your computer, remove the battery from the motherboard for 2-3 minute. put the battery again into motherboard, start your PC, All Bios setting will get resettled and you an use USB port till your PC admin know that Your PC BIOS is in resetted condition. For more information about BIOS resetting read here.