Uninstall any other antivirus software
Prior to installing Microsoft Security Essentials, please uninstall any other antivirus software on your computer.
Download Microsoft Security Essentials from the link below
In the web site, you may need to select the appropriate Language and Windows version.
Checking the version of Windows
If you are unsure which version your operating system is, click on the Windows Start button at the bottom left hand corner of your screen and right click on Computer in the right hand menu pane. Click Properties. This will open a window which shows you information about your operating system. For example, in the illustration, the Operating System is Windows 7, 64 bit. Windows edition shows that it is Windows 7, and under System, System type shows that it is 64 bit.
Accept the License Agreement
Ensure that you agree with the Microsoft Software License Terms and click I accept.
Click Install and Restart
Assuming that you have uninstalled any other antivirus programs, click Install.
Please wait while this wizard installs Security Essentials on your computer. This might take a few minutes.
Once the installation is complete the screen will ask you to restart your computer. Click Restart now.
Restart once the uninstallation is complete.
You should see a Preparing to remove... dialogue.
On the next screen asking "Are you sure you want to make these changes" clickYes. The windows installer will now remove McAfee.
Restart your computer once the uninstallation is complete.
Restart your computer once process is conplete.
Open a new window and paste in the the following link https://www.sophos.com/en-us/products/free-tools/sophos-antivirus-for-mac-home-edition.aspx to go to the Sophos site.
Follow the steps to register and download the installer.
Open Downloaded File
Open downloaded file. Bring new window to front.
Open your Downloads folder. Your browser may have unzipped the download automatically, if not then double click on the zip file (normally called savosx_he_r.zip)