Disk utility does'nt recognize my HD

Hello,

cant find my internal drive anywhere !!

cant start my macbook !!! try to do everything! when it did show the "macintosh HD" in the disk utility from the installation dvd:

Tried to erase it and it stoped and gave me: "there was an error on erasing please restart..."

Tried to reinstall leopard and it stopped and wrote:"couldnt complete bla bla... restart and try again..."

Tried to restore from Time Machine: -------> couldnt... please restart and try again !!!

Now it didnt even show any hard drive any more on th macbook HHEELLPP !!!!

anybody?
thanks.