I want to uninstall and completely remove QGIS installation from my computer(windows vista). I have uninstalled it and when i try to reinstall it says it is already installed on the system.
You can make sure all folders in your hard drive and your
.qgis2 folder (
C:/Users/You/.qgis2) are deleted. You could also delete the Registry entries for QGIS by running the regedit program and searching for QGIS:
Hopefully when you restart your computer, you will be able to reinstall QGIS again.
Hope this helps!
There are comprehensive uninstall programs available which do thorough searches and removal for all leftover files and registry values which should solve the problem. An example is Revo Uninstaller.