See if you can get into safe mode and attempt to uninstall IE 6 as detailed below
To get into the Windows 2000 / XP Safe mode, as the computer is booting press and hold your "F8 Key" which should bring up the "Windows Advanced Options Menu" as shown below. Use your arrow keys to move to "Safe Mode" and press your Enter key.
NOTE: You must be logged on as Administrator or as a member of the Administrators group to remove Internet Explorer 6 on a Windows 2000-based computer. After you remove Internet Explorer 6, you cannot remove the earlier version of Internet Explorer that remains on the computer.
1. Quit all running programs.
2. Click Start, point to Settings, and then click Control Panel.
3. Double-click Add/Remove Programs.
4. In the Currently installed programs list, click Microsoft Internet Explorer 6, and then click Change/Remove.
5. Click Restore the earlier Windows configuration, and then click OK.
6. Click Yes when you are prompted to remove Internet Explorer.
7. Click Restart Windows to restart the computer.
8. Start Windows Explorer to verify that you no longer receive the error message described in the "Symptoms" section of this article.
9. Start Internet Explorer, and then browse to the following Microsoft Web site to download any security updates that are needed for the version of Internet Explorer that remains installed on your computer:
Microsoft Windows Update (
Microsoft Windows Update)