Which part of that multi-part suggestion did you try, exactly?
Well, OpenSSL only provides 32bit DLL's anyway, so they're the ones I initially tried. I then obtained a copy for x64, and mIRC still doesnt register itself as SSL ready.
So I'm kind of stumped from here. 32bit/64bit, tried multiple directories, I'm about to give up hope regarding mIRC/SSL/x64
