You are booting and running the MacBook using an external drive, is this correct?
If so, you could do this:
1. Boot from the external drive
2. When you get to the finder, open Disk Utility
3. Choose to "Erase" the internal drive (same as "re-initialize").
4. Choose HFS+ with journaling enabled. Give it a meaningful name.
5. Let DU re-initialize the internal drive.
When done, the drive should mount on the desktop, but there will nothing on it.
To copy over the OS:
Fastest, easiest, cheapest way:
(This assumes that everything on the external drive will fit on the MacBook drive):
1. Download CarbonCopyCloner from:
http://www.bombich.com/download.html
CCC is FREE to download, and it's FREE to use for 30 days.
2. Launch CCC.
3. Check CCC's prefs so that it is set to copy the recovery partition as well.
4. Put your SOURCE DRIVE (external drive) in the leftmost window.
5. Put your TARGET DRIVE (internal drive) to the right of it.
6. There is a popup regarding handling of data -- set this to "delete anything that doesn't exist on the source"
7. Now click the "Clone" button and let CCC do its thing.
When done, CCC will "clone" the external to the internal -- exact copy.
Now, power down, all the way off.
Disconnect the external drive and press the power-on button, THEN...
... immediately hold down the option key until the startup manager appears.
Select your internal drive with the pointer and hit return.
Do you get a "good boot"?
Let us know.
