how can i remove mackeeper ?

how to uninstall MacKeeper.http://applehelpwriter.com/2011/09/21/how-to-uninstall-mackeeper-malware/

Here's a more recent article: How to uninstall MacKeeper from your Mac | Macworld, and also see How to Remove MacKeeper.

"MacKeeper" is a scam with only one useful feature: it deletes itself.

First, back up all data.

Note: These instructions apply to the version of the product that I downloaded and tested in early 2012. I can't be sure that they apply to other versions.

If you have incompletely removed MacKeeper—for example, by dragging the application to the Trash and immediately emptying—then you'll have to reinstall it and start over.

IMPORTANT: "MacKeeper" has what the developer calls an “encryption” feature. In my tests, I didn't try to verify what this feature really does. If you used it to “encrypt” any of your files, “decrypt” them before you uninstall, or (preferably) restore the files from backups made before they were “encrypted.” As the developer is not trustworthy, you should assume that the "decrypted" files are corrupt unless proven otherwise.

In the Finder, select

Go ▹ Applications

from the menu bar, or press the key combination shift-command-A. The "MacKeeper" application is in the folder that opens. Quit it if it's running, then drag it to the Trash. You'll be prompted for your login password. Click the Uninstall MacKeeper button in the dialog that appears. All the other functional components of the software will be deleted. Restart the computer and empty the Trash.

☞ Quit MacKeeper before dragging it to the Trash.

☞ Let MacKeeper delete its other components before you empty the Trash.

☞ Don't try to drag MacKeeper from the Dock to the Trash. You must open the Applications folder as above.

☞ Don't try to remove MacKeeper while running in safe mode.