This is a generic error message. The actual error is located in:
"C:\Windows\Windows Update.log" (Windows 98/ME/XP)
"C:\WINNT\Windows Update.log" (Windows 2000)

If the error is accompanied by 0x800A0007 in the "Windows Update.log", download and install  Microsoft XML Parser (MSXML) 3.0 Service Pack 4 (SP4)

Please let me know what step works for you

Changed 5 January 2004

1. Try changing the URL prefix to "https" instead of "http"
If this resolves your issue, this is most likely a caching issue referencing outdated Microsoft data with your ISP.
This workaround may be necessary until your ISP clears their cache, usually less than a week.

2. Check Date/Time (Look Closely, this is a major cause of update issues).
Also verify the computer is set to the correct Time Zone:
Double click Clock in Notification area (bottom right corner normally)
Click Time Zone tab.

3.  You Cannot View Updates on the Windows Update Site Using Secure Socket Layer

4.  Go to Internet Options in the Control Panel:
Delete Cookies
Delete Files (check box "Delete all offline content")
Clear History

5.  Perform Disk Cleanup:
Start/All Programs/Accessories/System Tools/Disk Cleanup
Check all boxes except "Compress Old Files"
Click OK and follow prompts.

6.  Go to Windows Update
On the left column, click "Review and install updates"
Next time you visit the site, click "Scan for updates" as you normally do.
This has resolved this issue for at least a few computers.

7.  Editing the registry can cause the system to be unusable.
Know how to backup and restore it BEFORE attempting to edit the registry
HOW TO: Back Up, Edit, and Restore the Registry in Windows XP and
Windows Server 2003
Start/Run
Type "regedit" ENTER
On the left panr navigate to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
Click on "Lsa" so it is highlighted
Doubleclick "fipsalgorithmpolicy" in the right pane
Set the Value Data to 0 (zero).
Click OK, follow prompts and reboot.

8.  If the issue persists after trying the above, follow the Windows Update Checklist