Have you installed Musicmatch 10.0? If so that is your problem as Musicmatch released a very very bug ridden version that has reaked all kinds of havoc with XP SP 2. Many people including myself are having problems with Musicmatch 10.0.
After you uninstall MM, delete any remaining files left over in your program files folder. You might wanna try to repair IE through one of these 2 methods.
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.
If you have to reformat your drive then install MM 9.0 or earlier until MM properly releases a new version or fix. I found a link to 9.0 if you want it. It seems most of the problems are caused by the mim.exe and the "logging and tracing manager", both which are new to MM 10.0.
note - turn off check for new updates when it installs.
Just to give you a better idea of problems others are having with MM 10.0 here's a link.
Digital Music Weblog
I hope some of this was useful.