how to force windows to report a false hard disk serial number?

Just what I'm thinking for..to prevent un-regitered users from entering the lessons.. it is for an E-Learning System...

And I want every account for one PC only.. and the user have TWO TIMES only Activation.. so if he changed his HD he can reactivate.. as for example : if you registered for a learning course.. so if you was absent.. it is your falt not mine.. is that right?

So.. I hope you can help me with this.. but can we chat at one of the following IM :

Yahoo! Messenger : [email protected]
MSN Messenger : [email protected]
ICQ : 294571847

I'm waiting your add because you know.. there are many secret thing for the System.. I can't put it here.. So I hope you will agree to chat at one of the IM..

Regards