BOAC:
Keep in mind that the 'sleep' scheme is fine under Win7 for a power-saving initiative.
However, be very wary of 'hibernate'. It is not unknown for systems to enter the hibernate state and subsequently fall into a coma. One that is not easily remedied either.
Even here at work all the I.T. people have been instructed to NOT place systems into hibernate for that very reason.
(I have received no such instructions as it is known throughout that 'He doesn't do Windows. He's that penguin guy.')