Windows and QGIS 1.9.0
This is a step-by-step procedure (I recommend to double-click images for a better view) to install Win QGIS using the OSGEO4W installer instead of the standalone installer. The standalone installer, once downloaded, is not dependent on live internet connection but the OSGEO4W installer is. Huh, in that case, what's so fancy about the OSGEO4W installer? Well, the latter allows the user to install specific to package so if there are packages that you seek yet unable in the standalone then you know where to look for e.g. you won't find the Topology Checker in the official Release version but the Master version. I downloaded it from here because I found OSGEO4W installer at the QGIS.org download site not updated. I am keeping a step-by-step procedure of the 1.9.0 Master version here because many QGIS users in Malaysia still use Windows however seriously, they don't know what they are missing in terms of performance until they use Ubuntu instead but that's another story.