Mac Book not finding HD

Hello Everyone,
I have a Black mac Book I bought in late 2007. I have never had any problems with it or anything until the other day… It fell off my desk (I have no clue how). The file with the ? mark showed up. I googled the Fix and I tried to fix it, but The hard drive could not be found to install the OS. So I went to the Genius Bar, they said the HD was dead and that I had to replace it… So I decided to save the 85 bucks of labor and just go and get a better hard drive and put it in myself… Installed a Seagate 320MB no problem… Turn the Mac Book on, Put in the OS Disk 1… The Computer is still not finding the HD… Can you guys point me in the correct direction with my problem?
Thanks

Hi, welcome to the forums.

It sounds like you need to format the drive for OSX. New drives do not come pre-formatted so your going to have to do this during the install.

When your MB boots from the CD you will come to the install screen. Under the 'Installer' menu option you will see an option to 'Open Disk Utility'. At this point you want to use the disk utility to erase and format your drive.

Once this is done, OSX will be able to install.

Note, during the install, the installer disk provides help materials for this process. You may want to take a look at this if you aren't clear on anything. It's really not as complicated as it may sound.

from what i've read, it sounds like the lappy is not seeing the HD at all, so there is no way to format it with the disk utility on the OS dvd,. DU should see the HD, doesnt matter if its new, unformat, fat32, nfcs, fat or whatever.

my question is what do you mean the computer is not finding the HD.. am guessing the OP did not do step one, which is weird that apple would not give the choice when there is only one drive..

I had to format the HD... I am replying on my Mac thanks to you guys!!!!