Help: 15" macbook pro wont boot

[Unlockboot4s]

I bought a used 15 inch macbook pro, yesterday it crashed so i had to force shut it down, after that it would only get stuck on the apple logo and the boot spinning thing, i dont have the original installation discs, and time machine was turned off. So is there a way i can get my computer back running?
Thanks, any help is alpreciated.

 

[GGJstudios]

If you haven't already seen these, they may help:

Troubleshooting: My computer won't turn on
Mac OS X: Gray screen appears during startup

 

[Unlockboot4s]

I tried all of those... No luck
Im going desperate at this point

 

[Unlockboot4s]

Help anyone?

 

[bozz2006]

Do you have a friend who has install or retail OS disks? Try and restore or repair from there.