Sometimes our BHOs do not load all the time, so I found a way to always load a BHO in a popup window.
I work for a big firm, and I designed a BHO to help me, but I found that the BHO does not load in a popup window,
How to solve (tested in IE8)
In IE' settings, click 'tab settings', change "when popup window" to "always show in new tab".
Because BHO only loads in a new tab, you must set your IE to open the popup window in a new tab.
I hope that helps someone :)