There are some situations when Firefox struggles to replace Internet Explorer. Windows Update is one, as was validating Windows for Microsoft updates.

At least until recently in order to validate Windows or Office for a download you had to download a small program which would then give out a special code identifying whether or not the download was allowed.

Internet Explorer had an ActiveX plug in, making the process even simpler as there was no intervention required. It either gave you the download or not.

Now that's true for Firefox as well as there is now a Genuine Advantage plug-in for Firefox as the grab below shows.

It does suggest a certain acceptance for Firefox, not least because Silverlight is also available for it now.