Help - I've b*ggered up!

[BadHair]

A few weeks ago I downloaded "something" from the internet to stop spammy pop-up boxes appearing all the time (the sort you get on hotmail).
In my usual sensible fashion I promptly forgot what it was called and where it went on my computer. I now need to get rid of it as its seriously messing up my ability to publish to my work intranet.
I've looked in my program files but can't spot anything. Does anyone know a) what type of file this might be, so that I can search for it, or b) where this sort of thing would be likely to lurk, as its not where I thought it would be.
Sorry to be such a bobblehat.

Not a clue but what about checking dos ening in .exe, hope this in answer is not computerly naive

I assume you've tried looking under control panel, add/remove programmes in the hope that it appears there? other than that c:\windows\programme files is a good place to look and a name may ring a bell.

Found it now, and thank you Chandra and SoupDragon. As brain was in panic mode it never thought to look in add/remove progs, or that it might just be an .exe file.
It was a wishbone toolbar, if anyone cares. And I needed to get rid of it so I could add a link to Mumsnet from my intranet site!