I am tryin to download the app to upgrade my windows 8 to windows 8.1. I am using an HP Pavillion 2000. It starts the download then it tells me the app can not be installed error code 0x80240031. Please help! And thank you :)

Hi,

WU_E_INVALID_FILE 0x80240031:  The file is in the wrong format.

Please upload the WindowsUpdate.log file in forum which located in %Windir% folder.

You can boot into Clean Boot mode then try to download again:

How to perform a clean boot in Windows

http://support.microsoft.com/kb/929135/en-us