A lot of times depending on what utilities were used to eradicate such invasions, other things get brokwn:
1. Download and follow the instructions for "IEFix" - a general purpose fix for Internet Explorer (Win 98/ME/2000/XP):
Note: Else, some of the core Internet Explorer ".dll files" may not be correctly registered or need registering. First, verify the exact path of where the Iexplore.exe file is found and used as noted for the "Primary. . ." example. Second, click Start, Run, type exactly "Primary Hard Drive Letter:\Program Files\Internet Explorer\iexplore.exe" /rereg, and then either click OK or press Enter.
a. Registers Urlmon.dll, Mshtml.dll, Actxprxy.dll, Oleaut32.dll, Shell32.dll, Shdocvw.dll, [Q281679].
b. Refreshes Internet Explorer using IE.INF method. Note:
"Unable to Install Internet Explorer 6 on Windows XP (Q304872)"
"How to Reinstall or Repair Internet Explorer and Outlook Express in Windows XP (Q31837"
c. Initiates "SFC /Scannow" (Win2K&XP), [Q310747].
a. First, be familiar with "Information About Internet Explorer Setup (Q256340)". Second, click Start, Search, All Files and Folders, More Advanced Options, enter a check in Search Hidden Files and Folders, Search System Folders, and Search Subfolders. Type ie.inf in All or Part of the File Name box, select C: in the Look In drop-down menu or the letter of the hard drive containing the Windows folder, and then click the Search button. Find the file labeled ie.inf in the result pane. Right-click this file and then from the context menu, select Install.
b. The article [Q304872] states that when you try to install IE6, you may receive an error message that can occur if it has already been installed and the installation package does not contain any new customizations -- a customized versions of Internet Explorer 6 that was created by an Internet service provider, Internet content provider, or a corporate administrator that is installed instead of the default browser.
c. "How to Reinstall or Repair Internet Explorer and Outlook Express in Windows XP (Q31837."
3. "LSP-Fix" is a free utility that may be downloaded to repair certain problems associated with Internet software when you can no longer access Web sites due to bugs in the LSP software or deletion of software. LSP-Fix repairs the Winsock LSP chain by removing the entries left behind when LSP software is removed by hand (or when errors in the software itself break the LSP chain), and removing any gaps in the chain.