Versions on Windows have supported MIPS, Alpha AXP and 16-bit and 32-bit x86 but currently support only 32-bit or 64-bit. Current versions also run on 圆4, 32-bit ARMv7, PowerPC and IA-64. Originally Microsoft Internet Explorer only ran on Windows using Intel 80386 ( IA-32) processor.

Later versions were available as free downloads, or in service packs, and included in the OEM service releases of Windows 95 and later versions of Windows. It was first released as part of the add-on package Plus! for Windows 95 that year. It was a reworked version of Spyglass Mosaic, which Microsoft licensed from Spyglass Inc., like many other companies initiating browser development. The first version of Internet Explorer, (at that time named Microsoft Internet Explorer, later referred to as Internet Explorer 1) made its debut on August 24, 1995. Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated IE or MSIE) is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995.