signed ActiveX control doesn't ask to install, just gives me security error

I have this strange problem.

I have developed a control on my PC.

Now when I try to access this control on a page (on my local PC),

I get the error...

Your security settings prohibit ActiveX controls being displayed, as a result this page may not display correctly...

Now the control is signed, and I have added the site on my Pc as a trusted site. I have checked the settings so it should definately install the control. I have played with many settings etc.

But if I go and access the page from a remote PC, the control asks to be installed and works perfectly.

Why does this happen? My guess is somewhere in my PC the Activex is registered, and for some reason it doesn't want to load up.

This used to work, so something has got corrupted. Also I have removed any installed controls, but that doesn't help...

Any ideas?

Greg