How do I get rid of an unseen prim?

I have read other threads on invisible prims and ghost prims, but I'm not sure if the problem I'm having is this same thing. Here's the story: A few weeks back I bought a house off of slexchange, it was cheap and I just wanted to see how it would look on my land. I rezzed it, didn't like it and deleted it from my land. I check my prim usage in "about land" everytime I log on, just to make sure my auto return is still working properly, and I don't have litter on my land. Ever since I rezzed this house, when I click on "show" under all the items that are mine, it shows a piece of this house which I had rezzed but deleted. It's a big triangle shape that ONLY gives any indication of being there when I "show" my objects on my land. I've had ghost prims before which I could walk into as though they were there even though they were unseen. This particular prim is not solid in anyway. I thought the rolling restarts last week would take care of it (like restarts took care of other "ghost" prims), but it's still there. I can't click on it, can't select it, can't do anything with it. Now, granted, it's not bothering me by being there and it's only 1 prim so it's not causing me to reach my land prim limit by any means, but it confuses me. How do I delete something that can't be seen or felt unless I specifically highlight it under "about land"?

Hightly Transparant. - That doesn't seem to work with invisiprims for some reason (at least the one I accidently left at the Forum hangout).

How I found the invisiprim at the forum hangout - "drag edit". Start "selecting" everything on your land - drag that window, and you will find that invisiprim.

Can you see it when you show transparent items? ctrl+alt+t I think it is...you might be able to click on it if it shows then. If not, thats just odd! Never heard of a ghost prim hanigng around so long before, it likes you!

Are you sure it is a ghosted prim? It may be just a normal prim, but transparent. You can highlight these by selecting the 'highlight transparent' from the 'view' menu. Any transparent objects will be shown as semi-opaque red, and you can then delete it.

Maybe that's the problem...I need to highlight transparent. The weird thing is that I remember that piece of the house before I deleted the house, and it wasn't transparent. So, you can only "select" transparent items if they are highlighted, even if you know they're there when they're not highlighted? (I'm not even sure that question made any sense, but not sure how to re-word it....lol).
Thanks for everyone's help so far. I'm going to go to lunch now, but will be back to see if that's all I need to do to end this mystery.

If I am in edit mode I have accidently hit a transparent prim once or twice, its just hard to find. If you arent in edit mode, I think its near impossible to start an edit on a transparent prim cept for the drag box method of course. Once they are shown with the ctrl+alt+T (same as show transparency tip above) I have always been able to click on a transparent prim though. Good luck with your tirangle! Maybe it was a transparent prim that got stuck in the build that the builder didnt see?

It could be. I'm going to try out highlighting transparent tonight and see if I can click on it then. Thanks for your help everyone!