as long as they didnt throw you a Non-overclockable motherboard at you. yes you should be able to overclock just fine. Do you know what Model Motherboard it is?. Z75,Z77, B75... etc. u could probably get 4-4.2ghz easily just with playing with the multiplyer if you dont feel like overvolting it at all.
well like i said it's a pre-built pc by HP... so the motherboard is called "PEGATRON CORPORATION 2AD5" i really have no idea what that is... also i was playing with the thought to upgrade a few things. i kinda bought this pc, cuz i really liked the case ( yes i know dumb reason) plus it is fast etc etc