You should be using Bitlocker on your machine (which btw is faster on Win 7 compared to Vista). When I enabled this on my laptop running Win 7 – I did not get the option to also add a PIN – not sure if I did something wrong or by default it does not ask for it.
In any case, if you also want to add the a PIN on boot up then you can use the following command in a command prompt or power shell (with admin privileges) to enable this. Of course replace the “c:” with the drive you want to do this for.
manage-bde -protectors -add c: -TPMAndPIN