There are several options to choose from when you expand the QGIS folder from the Windows Start menu. (Below is from an installation of version 2.14.17). To perform analysis and build a map, you'll typically want to choose QGIS Desktop (5 & 6, below).
- GRASS GIS: Opens the GRASS command line and GUI interfaces. GRASS (Geographic Resources Analysis Support System) allows users to complete advanced spatial analysis on raster data.
- OSGeo4W: Standalone software packaged for Linux distributions.
- QGIS Browser with GRASS: QGIS Browser as well as the GRASS software
- QGIS Broswer: Preview your data and look at the metadata
- QGIS Desktop with GRASS: QGIS Desktop as well as the GRASS software for advanced raster analysis
- QGIS Desktop 2x: Analyze geospatial data and create maps
- Qt Designer with QGIS custom widgets: Standalone software that allows users to build custom GUIs
- SAGA GIS (System for Automated Geoscientific Analyses): Open source standalone software used to run geoscientific modules.