MacBook Wont boot past apple logo screen.

Hi, I am new to iFixit and will do my best to make this as detailed as possible. Hopefully someone else has encountered this problem before and can help me out! If my two hours of researching wasnt enough to find an answer that is already here I appologize ahead of time.

My Macbook Pro A1278 stopped working late last month. It has been sitting since then until last night I decided to try to fix it.

Fault #1: Macbook will not power on.

*no response when plugged in with 60W magsafe power adapter or just on battery. Tried another 60W cable, no change.using google i came accross a solution..

Solution #1: Remove magsafe adapter. Remove Battery, Swap RAM Slots(not sure why i was told to do this), Hold Power button 10 seconds, Replace magsafe adapter, Hold power button for 10 more seconds, then power on.

*Now my macbook will power on only without the battery installed, which leads me to believe the battery is not serviceable. Once powered on i was able to log in, view my files and folders, listen to music, everything seemed fine. I did a proper shut down and when powered on again another fault was found.

Fault #2: Macbook will not boot past apple logo screen.

*The macbook makes the "chime", then the apple logo appears with the small loading wheel and a progress bar beneath it, the progress bar will slowly load to 100% then the macbook will power down.

*I tried booting with COMMAND + S then typing "/sbin/fsck -fy"

Throughout the different checks i always get "Incorrect number of thread records (4, 225)" four times after "Checking catalog file", followed by other checks then it says repairing volume.

When it is complete it says "The volume Macintosh HD could not be repaired after 3 attempts. The volume was modified."

I type reboot then it will try to boot normally and power down again once the progress bar on apple logo boot screen reaches 99%.

I am not farmiliar with apple products and how the systems work. Could my HD be no good? It worked fine after solving Fault#1 and didnt get removed or dropped.

Please help :)

Thanks!!

Tyler.