astovall0 :
yes it is a usb keyboard but it will let me enter setup and boot menu just not bios and motherboard i believe is a Dell
It looks like the Dell Gx620 doesn't have a ps/2 connector, so you should at least be able to get into the bios even with a usb keyboard. However, depending on your display, you might not see the prompt for that in time to use it. Try repeatedly pressing the F2 key as soon as you've pushed the power button. However, motherboards for prebuilt computers almost never allow overclocking, and even if one did, overclocking with stock cooling is a bad idea.