Automatic Updates memory hog on XP SP3. Updates not working.

The issue is I'm not able to see what KB Number updates are needed.

The Microsoft Updates page stays on the "Checking for updates" page and increasingly uses CPU and Memory untill the computer is unresponsive and AU Service is consequently stopped.

I'm not at work at the moment but I will check soon to see if i can disable Microsoft Updates, but maybe there is a registery setting to roll Microsoft Updates back to just Windows Updates?

Thanks for that. The Updates now gets all the way through checking for updates.

I think renaming datastore.edb also helped. For anyone having issues, please try the following and turn off Microsoft Updates to see if this solves the issue-

You can find out if the update database is the cause of the issue by
temporarily moving it to either the Desktop or Recycle Bin.
It's located in Windows\Software Distribution\Data Store and named
DataStore.edb. In order to move it you must first stop the Automatic
Update (AU)service and, if started, the Background Intelligent Transfer
service (BITS).
Click Start > Run > type in
cmd
Click OK or press Enter

At the prompt type in the following commands, pressing Enter after
*each* one

net stop wuauserv
net stop bits
exit

Now move DataStore.ebd to a temporary location. Another copy of it will
be recreated when the AU service starts on boot.

Restart the system now and see if the issue still persists.
If it does, then stop the previously mentioned services once more and
delete the contents of
Windows\Software Distribution\Download
Restart and see if the issue persists.

To avoid the issue in the future suggest you configure Antivir to *not*
monitor
Windows\Software Distribution\Data Store <--- this subfolder

Source: http://support.microsoft.com/kb/822158
Although the title of the KB article has been changed it still applies
to Home XP systems.

<QP>
What are the differences between Windows Updates...and Microsoft Updates?

While Windows Update provides you with updates specifically for Windows, Microsoft Update expands the service to download and install updates for other Microsoft software, such as Microsoft Office and Windows Live [as well as Silverlight & Microsoft Security Essentials]...
</QP>
Source: http://www.microsoft.com/windows/downloads/windowsupdate/FAQ.mspx

If you configure Windows Update as your default update source, Automatic Updates will NOT offer ANY updates for MS Office, Windows Live Essentials applications, Silverlight or Microsoft Security Essentials (if installed).

While "flipping" to Windows Update may have (temporarily) resolved the behavior, having Microsoft Update as your default update source may not have been the cause of the behavior. 

Good luck with that!

Yes, I suggested that you MAY be seeing the effects of a hijackware infection but I didn't say that was definitely the cause of the behavior.

NOD32 is not perfect (cf. http://kb.eset.com/esetkb/index?page=content&id=SOLN2523) nor is any other AV app.

Many, many Trojans/hijackware disable ALL security applications. 

Same problem for me.

I applied Micarl solution which consists to stop windows update service and to delete datastore.edb, under 2 virtual XP Mode.

It solves problem on first VM, but not on second which continues to hang on because of MU client, even repeating solution twice.

This problem appeared about a month. No trouble before, with same configuration.