SGS3 wont boot.

Hi!

I have used my S3 for a couple of months and i am very satisfied with it. But yesterday when I rebooted, it got stuck on the samsung logo and wouldnt go any further. Tried rebooting it a couple of times but with no success. I then tried to wipe data and cache but it said that it failed to mount /system /data. I have not modified the phone in any way and I was running Jelly bean. Is there a way to fix this on your own or do i have to send for repair?

Thanks in advance.