problem while reinstalling IDE

I was comfortably using the ARDUINO IDE v1.8.0. But for some stupid reason I wanted to check v 1.6.13 While I tried to install this older version, during uninstallation of 1.8.0 some thing went wrong and an error appeared.

Error opening file for writing: C:\Program Files(x86)\Arduino\hardware\tools\avr\lib\libavr-sim.a

Now I am unable to uninstall and reinstall neither v 1.8.0 nor v 1.6.13. I am using windows 8.1 Urgent help needed please.

Here is some additional information...when I open the "File Explorer" , I can see probably partly installed "Arduino" program under C>Program Files(x86)>Arduino. But if I go to "Control Panel>All Control Panel Items>Programs and Features" I cant find the "Arduino" program there for uninstalling. Is there a way to completely clean the mess, and start afresh for installing the IDE ?

I don't know the solution for your uninstallation issue but here's a workaround: On the Arduino download page you will see there are two different Windows links for each release, "Windows" and "Windows installer". If you use the "Windows" download then there is no need to uninstall or install the Arduino IDE, you just unzip the downloaded file and you're good to go. This is especially useful when you want to have multiple versions of the Arduino IDE installed on your computer because you don't need to uninstall one version to install the other.

And as an additional bonus some info attached that might be useful.

CLEAN UP BEFORE INSTALLING ANOTHER COPY OF THE IDE OR ARDUINO CREATE.pdf (345 KB)

Hi Friends...many thanks for ur prompt help...let me try both options (using .zip file and CLEAN Arduino) one after the other, hopefully some where I will be lucky enough to resolve the issue....