Cannot reinstall iHate Spam

IHateSpam not Working. When I did a repair on OUtlook 2003 under XP Pro SP3, the toolbar on Outlook disappeared and IHS stopped working. I clicked about About iHatePam in the system tray and this indicated I was running uner version 4.0.633, but I knew I had installed at least 5.3 in the past, so I did an uninstall from the control panel and tried to reinstall 5.3. I now receive an error message that another more recent version is running and later asked if I want to uninstall. I select uninstall, but this does nothing. I cannot see this later verison in the control panel to uninstall, so I am stuck.