T20 screen displays mac address id every now and then

[xgator]

After I reboot the laptop this error disappears and I get a no hd found error. So I turn off the laptop and wait half an hour and restart the machine succesfully. However in the morning I receive the same black screen with the MAC address ID and i follow the same reboot steps.

Can anyone explain this strange behavior? javascript:emoticon(':?:')
Question

My original HD failed completely so I bougt a brand new one and it seems that this one is going to crash/fail too. I hear clicking sounds when the laptop boots at times. Last time this happened my HD crashed. Is the system board causing this ?