White screen upon booting

Hi I need some help my macbook pro 15" (os lion dont know what version) went to sleep and ran out of battery, when i charged it and tried to start up it wouldn't so i did a force shutdown (press power for 10 secs), now when i reload it loads the bar on the bottom for about 1cm then the bar disappears and the white screen with the apple logo stays with the loading sign spinning again and again.. doesn't do anything after an hour or so i've given up.
I have read through numerous previous posts, from what i have gathered,
I have run the "command s" and $fsck -y and tried to fix the disc but it shows:
** /dev/rdisk0s2
** Root file system
Executing fsck_hfs (version diskdev_cmds-540,1~25)
** Checking Journaled HFS Plus volume
The volume name is Macintosh HD
** Checking extents overflow file.
Invalid leaf record count
(It should be 577 instead of 579)
** Checking catalog file
Incorrect block count for file bounds
(it should be 1 instead of 0)
Keys out of order
(4, 12661)
** Rebuilding catalog B-tree
** The volume Macintosh HD could not be repaired.
**** FILE SYSTEM WAS MODIFIED ****
So what do I do now I know B-tree is a corrupt file. I dont have time machine and haven't backed up my files in 6 months. its actually due for backup this weekend!
I went into Disk Utility to run repair disk but it says "Disk utility cannot repair this disk. Back up as many of your files as possible, reformat the disk and restore your backed-up files.
My question is, how do I recover my files. Once I get my files I can reformat
Any suggestions please. Thank you so much! PS. I'm a comp illerate so please simple slow steps in explaining

After 4 nights and numerous research hours later I have finally fixed my corrupted Mac HDD. (Macbook Pro early 2011, OSX Lion 10.7.2)
I don't want all this effort going to waste so I'm going to give some step by step instructions on how I managed to fix my MacBook Pro. Idiot's guide because I am not that great with computers..
Presenting Issue:
When powering up Mac, unable to load the OSX. It goes into a white screen with the apple logo with the loading sign spinning below. A grey bar below that shows up and starts to load but disappears not long after. The loading sign continues to spin but nothing happens.
Diagnosis:
- Shutdown computer. Press power button, then press "command S" straight away and hold, you will hear the chime and wait till the terminal screen loads (this is a bunch of white text). Then release buttons and wait till it stops. Type "FSCK -Y" (without the ""). Wait for it to run. If the disc is broken it will try to repair itself. If that works then you are good. You can type "shutdown -r now" and restart computer it should load normally.
- If you have my problem it should say something along the last few lines of:
** Rebuilding catalog B-tree
** The volume Macintosh HD could not be repaired.
**** FILE SYSTEM WAS MODIFIED ****
This means the computer was unable to repair the HDD for you.
If you have backed up your computer then you can skip this next part. If you haven't (like me) then you will need to retrieve your files from your corrupted HDD.
Note: If you have a B-tree error you will not be able to use firewire (below) to access and erase your disk, nor will you be able to unmount your disk. When you try it will tell you it cannot be done. Also you will not be able to reinstall OSX onto the corrupted HDD - if you go into "command R" restore (below below), the disk will be greyed out and say it is in use and cannot be booted.
Resolution (Retrieve Data from a unbootable Mac):
- You will need to buy a IEEE 1394 800/800 9pin to 9pin firewire cable. If you live in Australia, I found one from Dick Smith for $10, where other electronic stores sell between $20-$60.
- You will also need your friend's MBP (or any other Mac that has a 9pin firewire port).
- Plug both MBP on their power supply. Turn the normal MBP on. Plug the firewire cable into both computers. Then press the power button once on the unbootable MBP and press T straight away and hold until the normal computer detects the broken MBP as a external HDD (it shows up as a yellow rectangle shape icon). The broken computer will also display a screensaver with an icon moving around.
- The normal MBP will detect your Mac HDD but it will display an error message informing you the disk is corrupted and unmodifiable. Press ok to ignore.
- You can now access your unbootable MBP as an external HDD. It is the icon on the desktop "Macintosh HD". Copy the files you require. Then press the power button once on the broken MBP to turn off firewire transfer. Unplug firewire cable. Done !
Resolution (Installing OSX Lion)
- You will need a previously partitioned disk on your broken MBP which is not corrupted which you can erase and use to format OSX Lion or a 3.5" external HDD. If you are lucky enough like me who likes to keep a random spare partition you are in luck. If not plug the ext HDD into the USB port with the MBP off.
- Turn on the MBP and press and hold "command R" until you hear the chime and until the grey recovery screen loads (I think this works if you have osx lion or mountain lion. If you have snow leopard you will need to insert installation disk instead).
- Select language and select reinstall a new copy of OSX Lion. This will take you to the installation screen. You will need internet access so either use airport or plug a direct ethernet cable (quicker d/l speed, faster installation).
- Select installation site as the spare partitioned disk or the external HDD. It will then download OSX Lion onto that disk (took me 2.5 hours), and install OSX Lion (took me 30 mins).
- Bazinga! OSX Lion installed.
Resolution (Erasing Unmountable Macintosh HD)
- Once your OSX Lion is installed and your computer is up and running again, you can now go into disk utility and select your Macintosh HD. Press "Unmount", it will go grey, and then select OS X Extended (Journaled) format, press "Erase" to do a 1-pass erasure of the HD. This should take a few minutes max and then check if your Macintosh HD is empty. TADA!!! New HDD.
- If you are crazy like me you can spend a good 7 hours and perform a complete 7-pass erasure. To do so go to advanced settings and change the erasure type.
Resolution (Copying OSX Lion to Macintosh HD)
- Now you can reverse the action by restoring the OSX Lion into your original Macintosh HD disk, and then erasing your partitioned disc.
- I'm sure you can just copy the disc and then erase but I'm not risking any more issues so I'm doing it the hard long way.
Fixed. If I took it into Geniuses they will tell me my HDD is dead and needs replacing. No way when I trust my gut instinct that it's a corrupt HDD.
Good luck guys. I'm now off to get my much deserved and deprived SLEEP! Hope this helps!!

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