Issues with Macbook booting up

Hi All,

So day before yesterday my Early 2011 Macbook Pro was acting all crazy and working really slow. So, I tried to power cycle it by pressing the power button. Now, the laptop came back on - I chose the user profile I wanted to use (between Guest and myself) - entered the password. The system got stuck at the loading bar with 50% done. After that it stayed there forever.

I searched a lot of forums, and the tricks didn't work. I tried recovery mode, turning off WiFi and restarting, but nothing worked. Then, I tried to "Verify and Repair" my disk in Disk Utility and it failed by throwing and error : "Couldn't mount disk". I got really worried about my data. So, I grabbed a Thunderbolt to Thunderbolt cable - and hooked it upto another Mac and got the important data.

So, my question is that Disk Utility is saying that it cannot mount disk, yet using thunderbolt cable I was able to get most of the data out (I left others, because, they just wouldn't start copying and get stuck at Preparing to copy 123 items). I also tried to partition the start up disk in disk utility and it gave me an error that it need file system resize support.

So i am stuck.

Please help me guys.

Thanks!