You need a SATA notebook drive and an external case. put new drive in case. Clone existing drive to new drive. Make new drive you boot drive and then swap it into Macbook. Download SuperDuper to clone drive

If you have an aluminum macbook, then just remove the battery cover and unscrew the one 00 phillips screw (with a 00 phillips screwdriver), then remove and disconnect the hard drive. Connect the new hard drive, put it back in place and screw the screw back in.

If you have a white or black macbook, then you need to remove the battery. On the sides of the battery bay you will find 3×00 phillips screws. Unscrew them. Then you will remove the L-shaped panel that constitutes the sides of the battery bay. There should be a plastic tab on the left side of the bay (the short side of L). Pull on the tab firmly and the hard drive will come out. Slide in the new hard drive (put the adhesive plastic tab on it in case you ever need to replace the hard drive again). Put L-shaped panel back in and screw back in the 3 screws.

After you are done changing out the hard drive, you need to reinstall the OS. Hope you have the Install discs around. Otherwise, you’ll need to order them from Apple.