MBP not booting, but HD seems fine
That's either a disk on it's way out or something has been corrupted and the OS is having problems mounting the drive.  

Do you have your system disk?  If so, you could try booting into is by holding the C key while booting and run Disk Utility, then do a permissions repair and a disk repair if you can.  

What fsck command did you enter?  fsck -f ?  If not then you should try that too.

If you can get into single-user mode then you can run the following command to repair permissions:

sudo diskutil repairPermissions /