Here are instructions: I found them here http://applehelpwriter.com/2011/09/21/how-to-uninstall-mackeeper-malware/
1. Go first to your Applications folder and throw MacKeeper in the trash. If you assigned MacKeeper to be pinned in the Dock, drag the icon off the Dock and release it over the desktop. It will, satisfyingly, disappear in the ‘poof’ of a cloud.
2. From your hard disk icon, go to your Library folder and look in Application Support folder. Trash the folder called ‘MacKeeper’ (/Library/Application Support/MacKeeper)
3. Still in Library, look for and trash any of these you find:
4. Now look for and trash all the following in the hidden Library folder in your Home folder. Use the ‘Go’ menu in Finder’s menubar and hold down the ‘Option’ key. Choose ‘Library’ from the menu (yes, this is a different Library folder from the one sitting in the root directory on your hard disk):
Don’t worry about deleting the wrong files. Basically, if it’s got either the words ‘zeobit’ and/or ‘MacKeeper’ in the file name, it needs to go. Do a Spotlight search for these two terms (separately) in case there’s any other stragglers lurking about.
6. Go to Applications > Utilities > Keychain Access.app and double click on it. Notice the padlock in the window is up there on the left, rather than down the bottom. Click on it and enter your admin password. Now go through all the items in the ‘Keychains’ list (such as Login, System, Root) with ‘All items’ selected in the ‘Category’ list. Anything you find related to ‘MacKeeper’ or ‘zeobit’, click on it, then choose Edit > Delete from the menu.
(Thanks to Al for mentioning this point in the Comments below! ).
7. When you’re done filling up your trash can with all this junk, click on the Finder> Secure Empty Trash...
8. Open the Activity Monitor utility (Applications>Utilities>Activity Monitor.app), make sure ‘All Processes’ is showing in the drop down menu just over on the right of the dialogue box, then scroll down the list and see if any processes called ‘MacKeeper’ (or ‘zeobit’) are still running. Older versions of MacKeeper may have a ‘WINE’ process running. If you find anything of this sort, click on it and hit ‘Quit Process’ (top left).
9. After all this is done, restart your Mac. Everything should be back to normal, but check the Activity Monitor one last time to be sure.
10. Finally, if you feel the need to have some kind of software watching over your downloads and attachments, there’s only one widely recognised program you need (and its free):ClamXav.