Stand alone meaning that it's not networked to any other machines.
Do you have a virus scan program on there? And you may want to try Ad-Aware available at http://www.lavasoft.de/
Right now their site is down for some reason.
Have you tried repairing IE yet?
Method 1: Microsoft Internet Explorer 6.x Repair for Windows XP
From the Start menu, select Run.
In the Open field, type sfc /scannow (Note: There is a space between sfc and /scannow)
Select the OK button.
Follow the prompts throughout the System File Checker process.
Reboot the computer when System File Checker completes.
Method 2: Microsoft Internet Explorer 6.x Repair for Windows XP
From the Start menu, select Search, select All Files and Folders.
Select More Advanced Options and place a checkmark beside Search Hidden Files and Folders option.
Ensure that Search System Folders and Search Subfolders are also checked.
In the All or Part of the File Name box, type ie.inf
In the Look In drop-down menu, select C: or the letter of the hard drive that contains the Windows folder.
Click the Search button.
In the search results pane, find the ie.inf file located in Windows\Inf folder.
Right click the ie.inf file and click Install on the context menu.
Reboot the computer when the file copy process is complete.