White Macbook Harddrive Problems

I'm sorry if this isn't in the proper section,

Basically I have an older macbook, (almost 3 years old), It recently has the problem of not starting up, when i turn it on it gives me a folder with a question mark flashing, I have done some researching and have learned that its not seeing my hard drive,

what I have done and still not working:

I have reinstalled OSX on it multiple times,
I have opened disk utility via install disk and repaired disk and permissions


The disk utility still sees my hard drive and when i open the startup manager on the startup it doesn't, so my first impression of it being a dead hard drive confuses me because if it were dead wouldn't disc utility not recognize it? But if its not dead then why won't the start up manager see it? If anyone has any suggestions on what I can try next it would be greatly appreciated...

Thanks

Since you've already wiped and reloaded it, I'd go to the partitions tab, set it up for a single partition, and under the Options button, make sure the drive is set for GUID partition map. It's possible the map got trashed along the way. However, with the cost of hard drives being so low now, I'd strongly recommend replacing the drive. Even if you get this one working, do you trust it with your data anymore?