I was able to remove OpenBD from my listing by cutting this:
<isapiFilters>
<remove name="OpenBD" />
<filter name="OpenBD" path="C:\openbd\connector\isapi_redirect-1.2.30.dll" preCondition="bitness64" />
</isapiFilters>
from this file: C:\Windows\System32\inetsrv\config\applicationHost.config
and then I restarted IIS, but my problem persists. :-(