I too had exactly the same problem as lady pink but, since I rarely use help, didn't know how long ago it went wrong. I looked up any relevant MS articles and found the one to which you referred, ie number 274736 but although this referred to the correct error message: ''The Initialization of the Help Center Failed'', the error number was different, ie 2147024893 instead of 2147143679 which is what lady pink and I both got. Nevertheless I did try the routine given in that article but, unfortunately, it didn't work.
I then searched Google and discovered the message from lady pink and your reply. Although your first link wasn't of any use to me, your second link lead to the MS downloads from which I installed the MDAC 2.8 SP1 components. I wasn't sure what they were supposed to do but, since you had pointed to this download, I thought I would give them a try and it did the trick!