|Did ALL the updates you just tried to install fail to install, or only some of them ?|
If it was ALL of them, have you run a Repair installation of Windows procedure, and it was only after you did that the updates will not install ?
(As in, you booted the computer from the XP CD, chose to run Setup, then chose "Repair your existing Windows installation" or similar, and Setup completed successfully.)
In any case, if it was ALL of the updates that failed to install, then you probably need to repair Registry entries for Windows Update related files....
It would be a good idea to print the following text.
E.g. Select the following text, RIGHT click on the highlighted area, select Copy, open Notepad, place your blinking cursor on it, RIGHT click , select Paste. In Notepad's top bar - File - Print.
Or use Wordpad for a better display of the longer lines - Notepad can mess that up.
Click Start, select Run and type the following:
cmd (click OK or press Enter)
net.exe stop wuauserv (press Enter)
(stops the Windows Update service)
regsvr32 wuapi.dll (press Enter)
regsvr32 wuaueng.dll (press Enter)
regsvr32 wuaueng1.dll (press Enter)
regsvr32 wucltui.dll (press Enter)
regsvr32 wups.dll (press Enter)
regsvr32 wups2.dll (press Enter)
regsvr32 wuweb.dll (press Enter)
regsvr32 MSXML3.dll (press Enter)
net.exe start wuauserv (press Enter)
(starts the Windows Update service)
Close the black Window.
Restart the computer.
Windows Update should then work fine
You can save yourself some typing by using the keyboard buffer - it saves what was typed in the last line.
Press the > cursor key to display the part of the last line that is the same, use the < cursor key if you need to back up, then type the rest of the line.