Use IE11 for legacy intranet sites. For modern web, use Firefox, Chrome (no longer updated on Win7), or Supermium (Chromium for Win7).
To always:
Internet Explorer 11 (64-bit) for Windows 7 ONLY - Microsoft internet explorer 11 32 bit windows 7
To understand the software, you have to understand the architecture. Windows 7 was widely adopted in two flavors: 32-bit (x86) and 64-bit (x64). Use IE11 for legacy intranet sites