Doh!

Am I getting thick?  I've had two things through my letterbox in recent days which I have found difficult to understand.  The first was a pamphlet about the imminent switch-over to digital TV and how it would or might affect me.  I've read through it a couple of times and I'm still not quite sure I've got my head round it.  And then I've had a letter from my bank saying that they are introducing a new security system for on-line banking and directing me to a web-site which would explain all.  Well I visited the site and watched the video, and I am now completely confused!  I've always regarded myself as reasonably intelligent, but I'm beginning to wonder if old age is catching up on me!