if u dont use ne USB peripherals like keyboard, mouse, webcam, speakers, ADSL modem, coffee heater, den u can go 2 d BIOS and disable all USB ports der and assign pw 4 d BIOS
but if u do use ne 1 of those den assumin u usin XP or above [even 2K]
How to disable the use of USB storage devices
2 allow acces only to certain sites and block access to d remaining u must use a sw dat uses white list as reference instead of a blacklist
heres 1 dat duz it
BrowseControl
but remember da as long as u allow acces 2 google, ur efforts wud b an exercise in futility