Although I have the macKeeper and I do virus scan.
I think that's the problem. MacKeeper is malware > https://discussions.apple.com/docs/DOC-3036
Probably, MacKeeper damaged something on OS X and made it unusable (that's why your Mac is starting from Recovery HD). Start your Mac on Recovery and reinstall OS X. You won't lose anything, and OS X should boot properly after reinstalling it. Then, after reinstalling OS X, uninstall MacKeeper > http://applehelpwriter.com/2011/09/21/how-to-uninstall-mackeeper-malware/
In general, we don't recommend any antivirus for Mac OS X because OS X has got its own security systems. See > http://www.reedcorner.net/mmg
However, if you want an antivirus, we recommend Sophos and ClamXav, not commercial antiviruses