Internet Explorer will not display HTTPS (Secure) pages

Just spent the last 2 hours trying to resolve a problem for a customer who could not log in to his Hotmail account. When I first looked at the machine which is running Windows XP SP2 and fully patched it was obvious that the problem was that IE could not display secure pages (those addresses that start with HTTPS://).

After a fruitless search for a solution, all of which suggested variations on clearing temporary Internet files and restoring all settings to their default state, I still had no luck. The last suggestion was to create a new user account and try accessing Hotmail from that... again no luck, same error message.

Finally I decided to check that Windows Update had been run recently, the customer had assured me that he did this religiously, and I was soon greeted with the error number 0x800b0001 and the usual nonsense from Microsoft which gives no indication as to what has gone wrong. After searching Google for 0x800b001 I found an article that suggested the following:

Register the following files with these steps:

Click on Start, Run and type "REGSVR32 SOFTPUB.DLL" (w/o the quotes). You should see a popup message that this process succeeded.

Click on Start, Run and type "REGSVR32 INITPKI.DLL" (w/o the quotes). You should see a popup message that this process succeeded.

Click on Start, Run and type "REGSVR32 MSSIP32.DLL" (w/o the quotes). You should see a popup message that this process succeeded.

Click on Start, Run and type "REGSVR32 WINTRUST.DLL (w/o the quotes). You should see a popup message that this process succeeded.

The first thing I noticed was that registering INITPKI.DLL took over 3 minutes to come back with the success message. But on completion of the above, Windows Update ran successfully. The bonus of this was that the above solution had also resolved the original issue of viewing secure Internet pages.

I'm really not sure why the above solved the problem, but I'm sure glad it did. I found it strange that not one of the sites we searched, Microsoft's included, did not mention any of the above as a potential resolution to our original problem?