Follow the prompts to install the update.When the file has finished downloading, go to your Desktop and double-click the file (it will be called mpam-feX86.exe, or mpam-feX64.exe).In the table left, click on the link that will work for your version of Windows.Check whether your version of Windows is 32-bit or 64-bit.How to download and install a Microsoft Security Essentials update:

Microsoft Security Essentials runs quietly and efficiently in the background so that you are free to use your Windows-based PC the way you want - without interruptions or long computer wait times. It's easy to tell if your PC is secure - when you're green, you're good. Microsoft Security Essentials is a free download from Microsoft that is simple to install, easy to use, and always kept up to date so you can be assured your PC is protected by the latest technology. If you still can't find the file you need, you can leave a 'message' on the webpage.Microsoft Security Essentials provides real-time protection for your home PC that guards against viruses, spyware, and other malicious software.If yes, please check the properties of these files, and you will know if the file you need is 32-bit or 64-bit. If you encounter this situation, check the file path to see whether there are any other files located in. There is a special case that, the operating system is a 64-bit system, but you are not sure whether the program is 32-bit or 64-bit. If your operating system is 32-bit, you must download 32-bit files, because 64-bit programs are unable to run in the 32-bit operating system. Microsoft Security Essentials is an effective antivirus program that provides real-time security. (Method: Click your original file, and then click on the right key to select 'Properties' from the pop-up menu, you can see the version number of the files)

If your original file is just corrupted but not lost, then please check the version number of your files. If you know MD5 value of the required files, it is the best approach to make choice Tip: How to correctly select the file you need

Mseinstall 64 bit