macbook stuck at white screen with bar

[subway3]

when i turn on my macbook it goes to this screen, then the bar dissappears after it fillsto that length and the circle keeps on spinning. I left if loading for a few hours and still won't start. does anyone know what the bar means? and how to save my mac?

thank you

 

[chscag]

You need to do some basic trouble shooting: Please see the following LINK. If you need further assistance, post back to this same thread and be sure to provide information about your machine and version of OS X you're running. Also tell us what you've done so far to try to resolve the problem.

Regards.

 

[subway3]

I have a macbook, not the newest one but the one before, running snow leopard. I upgraded the hard drive to a Seagate one because the first one died.

I've tried doing the command/option/p/r combo but nothing changed.

Thanks again.

 

[chscag]

Did you follow the trouble shooting steps in the link that I provided you? Specifically, did you try booting with your install DVD?

And, was the machine working OK before you swapped out the hard drive?

Regards.

 

[Fodge]

In that list I would put #5 after 6-12 and run the combo updater somewhere in there too.
[/2¢]

 

[EndlessMac]

Read this article from Apple's support site: Mac OS X v10.6: Gray progress bar appears under Apple logo during startup

You are going to need your Snow Leopard install disc.