Over the years I have tried QGIS and other mapping systems. Lately I wanted to make a go at using the newer versions of QGIS but wanted the ability to run the new one, 3.4 or 3.6 and to keep the old LTR 2.18 running parallel. I read that is possible through OSGeo4W.
Something went wrong in a DL or install and now I have versions of GRASS growing all through my Win7 64 bit system. (Growing Grass was a joke..) but GRASS is install all over in different versions, as is QGIS.
One helpful post suggested just deleting the normal C:\OSGeo4W directory.
I have tried just about everything and for my trouble, I have folders and files all around and they do not work or they error. (Although I must have deleted something else because now I can't produce an error, just nothing happens.
How can I clean this up? In searching it looks like there is no uninstall facility listed. ultimately I want to start clean with a new install.