Complex sentence: The initial focus of Windows Update was on free add-ons and new technologies for Windows; security fixes for Outlook Express, Internet Explorer and other applications appeared later, as did access to beta versions of upcoming Microsoft software, most notably Internet Explorer 5.
Split into simpler sentences: The initial focus of Windows Update was on free add-ons and new technologies for Windows. Security fixes for Outlook Express, Internet Explorer and other programs appeared later, as did access to beta versions of upcoming Microsoft software, e.g., Internet Explorer 5.