Could somebody help me to get rid of mackeeper?

Question

Advertisements everywhere. Can somebody make my day?

Answer 1

There is no need to download anything to solve this problem.
You may have installed the "Downlite" or "VSearch" ad-injection malware. Follow the instructions on this Apple Support page to remove it. It's been reported that some variants of the malware block access to the page. If that happens, start in safe mode by holding down the shift key at the startup chime, then try again.
Back up all data before making any changes.
One of the steps in the article is to remove malicious Safari extensions. Do the equivalent in the Chrome and Firefox browsers, if you use either of those. If Safari crashes on launch, skip that step and come back to it after you've done everything else.
If you don't find any of the files or extensions listed, or if removing them doesn't stop the ad injection, then you may have an adware variant not covered by the support article. Ask for instructions in that case.
The problem may have started when you downloaded and ran an application called "MPlayerX." That's the name of a legitimate free movie player, but the name is also used fraudulently to distribute VSearch. If there is an item with that name in the Applications folder, delete it, and if you wish, replace it with the genuine article from mplayerx.org.
This malware is often found on illegal websites that traffic in pirated content such as movies. If you, or anyone else who uses the computer, visit such sites and follow prompts to install software, you can expect more of the same, and worse, to follow. Never install any software that you downloaded from a bittorrent, or that was downloaded by someone else from an unknown source.
In the Security & Privacy pane of System Preferences, select the General tab. The radio button marked Anywhere  should not be selected. If it is, click the lock icon to unlock the settings, then select one of the other buttons. After that, don't ignore a warning that you are about to run or install an application from an unknown developer.
Still in System Preferences, open the App Store or Software Update pane and check the box marked
          Install system data files and security updates
if it's not already checked.