Mac OS Wiped out! Partition replaced with dis0s2

Hi!

I have a Mac Book Pro 13'' (early 2012) with OSX Yosemite and Windows 7 operating systems. There was a problem while booting, so I repaired the hard disk on disk utility when it prompted. Mac OS vanished and got replaced with "disk0s2". Now my Mac directly boots in to Windows. I don't have a time machine back up but I have manually copied Macintosh HD to an external hard disk from Windows, so my data is safe.

Can this be fixed or will I have to reinstall OSX? Will the online reinstall work without hassles in this case since the Mac Partition now shows as disk0s2" ? (Please check the screenshot: http://postimg.org/image/ni6se5011/)

Please help! Thanks in advance!

Boot and hold down th Option key and see if the Mac OS X partition comes up. If not a new install is on the books. Be interesting to see what happens with your copying the hard drive to a Windows external hard drive.

What actually happens when you click on disk02 in Disk Utility?

I had done that before and Macintosh HD didn't show up. Only Windows and Recovery were showing. Also, I couldn't repair disk0s2 partition.

Now, when I tried repairing the whole hard disk, disk0s2 had the repair option. So I clicked repair and it worked!

I was able boot into Mac now and it started up where I had left it!

Thanks a ton!!

Good work.