Running Windows Updates on XP and it has downloaded a bunch of updates but refuses to install them. It just whips through them all, announces they've all failed due to a problem on your computer, and offers to dump you into a useless "troubleshooter".
There is a WindowsUpdate.log file in your %winnt% directory (usually C:\Windows). Look through that.
Solution for 0x80004002
Press Start, then Run.
and hit enter, you'll get a little popup saying DllRegisterServer in WUAPI.DLL succeeded.
Repeat that step for these below..
Then try Windows Update again.
This worked for me. Allegedly it will work for error 0x8024400D as well.