The FileUp ISAPI filter is the "FileUpIsapi.dll" file that installs to the FileUp program directory. This dll is not and should not be registered as part of the installation process. It only needs to be referenced in IIS as an ISAPI filter in order to run. Removing the ISAPI filter, consequently only requires removing that reference.

Removing the FileUp ISAPI filter:
Instructions assume Windows 2000/IIS 5

1. Open the IIS Console.
2. Select your machine. Right click and choose "Properties".
3. On the IIS tab of the Properties dialog, find the Master Properties section (WWW Service). Chose "Edit...".
4. In the resulting dialog, select the ISAPI filters tab.
5. You may have several ISAPI filters installed. If the FileUp ISAPI filter is installed, it will show up in the list as "FileUp". Click the "Remove" button, to remove it.
6. Restart IIS. This can be done by typing 'iisreset /stop' and consequently 'iisreset /start' in the Run window off the Start bar.