There's a search box in the comp window, next to the current timecode. Open a comp, type the name of the effect into the search box, and it will show all layers with that effect. You can then click the effect on each layer and delete it.
joshweiland - that worked for one of the effects, I deleted it from the time line - so far so good. The last one (BCC Edge Lighting) is not showing up anywhere.
After flipping to all the comps and not finding the effect - AE crashed and now will not launch at all. Could I have caused this by deleting that other effect???
Removing an effect from a composition will not cause AE to be unable to launch entirely.
Can you open AE and create a new project?
Do you happen to know the exact version number of AE? It should be 11.0.2 (although, if you're a cloud subscription member, it shouldn't start with an 11 at all )