TaskHost.exe itself is a wrapper for dll or other exe and run as a windows service.
3 things to try
Before spending time hunting down what taskhost actual loaded. Check Event Viewer for errors. That may give out a quick answer or point you to the right direction.
Open Task Manager, go to Processes tab. On menu bar (top), click View -> Select Columns.... In pop-up windows, select Command Line.
That may give you an idea which dll taskhost.exe loaded.
Additionally, pay attention at the path of taskhost.exe. It should be
If not, you may have other problem.
Same idea as #2, but use a better tools. Download Process Explorer from Microsoft. It is free. It is able to give more details of running process.