learn to use google search, this is a update for windows defender anti virus, if you have some other anti virus installed, don't worry about it other wise:
KB2267602 is the latest Definition update for Windows Defender. Some updates require administrative permissions to be installed. Therefore, signing in as an administrator may help resolve the issue. Follow the methods to try and fix the issue:
Method 1:
Refer to the link and follow the troubleshooting methods to resolve the issue:
http://support.microsoft.com/kb/968003/en-us
Note: Scan for malware using Microsoft Safety scanner: The Microsoft Safety scanner expires 10 days after being downloaded. To rerun a scan with the latest anti-malware definitions, download and run the Microsoft Safety Scanner again. Any data files that are infected may only be cleaned by deleting the file entirely, which means there is a potential for data loss.
Check if you still receive the same error code while Windows tries to install the update. If yes, proceed to the next method.
Method 2:
Run the Windows Update troubleshooter to try and fix the issue. Refer to the link to run the troubleshooter:
http://windows.microsoft.com/en-in/windows/troubleshoot-problems-installing-updates#1TC=windows-8
If the update is still not getting installed, let’s reset the Windows Update components. Refer to the link to do so. Refer to the section “Windows 8.1, Windows 8 and Windows 7”
If the troubleshooter does not work, refer to the section “Manually reset Windows Update components” to reset Windows Update components manually from the link;
http://support.microsoft.com/kb/971058/en-us
Note: This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, you can refer to the following steps to back the registry files on the computer:
Press Windows and R keys to open the run box.
Type ‘regedit’ and press Enter from the keyboard.
Open the file option on the menu bar.
Click on Export and save the file with a name on the desktop.
If you want to restore the file, you can do so by double clicking the file that you have saved on the desktop.
For further reference, you can manually download and install the update from Microsoft Download center. Refer to the link to download the latest definition update:
http://support.microsoft.com/kb/923159/en-us
http://answers.microsoft.com/en-us/windows/forum/windows_8-update/windows-update-error-80070005-kb2267602/6cf718ae-c1ff-49fb-87c6-5ac46f140ff2?auth=1