My MacBook's bootable HDD was 'dead'.
I spent some time before realizing that the MacBook would never boot (even from an OS X DVD) if the installed HD had not been formatted for a Mac.
1) I formatted the new HD on another Mac, connecting it as an external HD.
2) I removed the 'dead' HD from the MacBook and replaced it by the newly formatted HD.
3) I booted the MacBox using an OS X DVD.
4) I restored OS X on the new HD using Apple's via-Wifi recovery procedure.
Do not hesitate to use iFixIt to replace a HD.
If you don't have two left hands (actually I am left-handed :-) you should make it.
I received iFix parcel only two days after ordering it on the US site (I leave in Europe). The tools (screwdrivers) are of excellent quality.