this is going to sound odd, but you have both service packs instaled on your computer right? if you are not quite sure if you could post the header of a HJT log in your next post that whoudl be great. IE 7 Beta is just that, a beta, and if you dont have thoes service packs it is quite likely you have corruped something.
try this repair for IE:
A number of XP users have reported situations with Internet Explorer 6 becoming corrupted and reporting a number of different errors. While there is certainly no guarantee, the two procedures listed below have restored functionality to IE6 for many users experiencing problems.Note:
Both methods listed require that the Microsoft Windows XP CD-ROM be available.
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
Follow the prompts throughout the System File Checker
Reboot the computer when System File Checker
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
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
Click the Search
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.
Microsoft Knowledge Base Article - 318378 How to Reinstall or Repair Internet Explorer and Outlook Express in Windows XP