Mackeeper has been known to cause more problems than fix, all the posts here say don't use it and offer instuctions on how to remove it, which is not as easy as just dragging it to the trash.
I am willing to guess that some of the third party software could be the issue.
Try a safe boot:
http://support.apple.com/kb/HT1564
Starting up in “safe mode” may help you diagnose problems you’re having with your Mac.
Note: To print these instructions, open the Help Viewer’s Action pop-up menu (looks like a gear) and choose Print.
- Shut down your Mac and wait 10 seconds.
- Press the power button.
- Immediately after you hear the startup tone, hold down the Shift key.You should press the Shift key as soon as possible after you hear the startup tone, but not before.
- Release the Shift key when you see the gray Apple logo and progress indicator (spinning gear).
To leave safe mode, restart the computer normally without holding down any keys during startup.
If you still have problems I would take it to Apple, there seems to be something strange going on here.
You search remove mackeeper on this forum, and get rid of it.