Windows Vista Update Error Code 80240016

Cause
The error message code 0x80240016 in Windows Vista is the result of the Windows Update application's inability to access specific user data.
Basic Troubleshooting
If you are experiencing this error, try restarting your computer. If a restart does not resolve the issue, you may need to stop and restart the Windows Update service manually from a command prompt using these commands:net stop wuauservnet start wuauserv
Advanced Troubleshooting
Additional steps to resolve this issue are available from Microsoft. The process involves stopping the Background Intelligent Transfer Service (BITS) and the Windows Update services and deleting some files that may be corrupt. See Resources for full instructions.