changing a laptops hard disk is no big deal.
i am a vaio user and ive done this procedure twice.
on the back of the laptop there are two covers which can be opened easily(only one screw) and it will be apparent
that they are meant for upgradable parts(only ram and hard disk of vaio can be upgdraded)
try and open both of them one will be for ram and other will be hard disk drive.
for removing hdd completely ul have to open 3-4 more screws. open them carefully and slide the harddisk a little bit back and
take it off.
then replace the hard disk..
im sure ul be able to accomplish this very easily. be careful though