To resolve Windows Update error 8000FFFF, try the following steps:
1) Launch REGEDIT
2) Go into HKLM\COMPONENTS, and check if these three values exist under the COMPONENTS key:
3) Providing they do exist, back up the Components key, then delete the three above values.
4) Restart the computer, and Windows Update should now be working fine.
If "HKLM\COMPONENTS" isn't there, then use the FIND tool and search for each of the three values individualy. I deleted two of them and couldn't find the third (actually NextQueueEntryIndex)