I have been using the ESET Smart Security trial for sometime now, however I wanted to install a new version of the software, so I uninstalled the earlier version of the software and tried to install the new version.

However due to some problem, I was unable to uninstall the software completely and it left me wondering what I did wrong, no matter what I tried or what I did, the older version could not be uninstalled, and while trying to overwrite the software with the never versions, I kept coming across permission denied error every time.

However I was able to remove the older version of ESET manually and then reinstall a fresh version, for those who are interested, here are the steps you need to perform.

Step 1: Boot the computer in safe mode, press the F8 key while rebooting and choose Safe mode from the list.

Step 2: Make sure that ESET service or any related services  are not running, or else you will not be able to perform the next steps.

To do that go to Start > Run and type in services.mscwithout the quotes.

In the services window, search for services that begin with ESET, stop the services if they are already running, and delete the services. There will be possibly two services related to ESET named ESET Service and ESET Http Server.

Step 3: Go to C:\Program Files and delete the ESET folder, if you have multiple ESET products installed, only delete the one that you want to uninstall from within the ESET products. Change the drive letter to the drive where windows is installed. 

Step 4: Go to Start > Run and type in Regedit to open the registry editor, in the registry editor, navigate to HK_LOCAL_MACHINE\Software and delete the entire ESET key.

You will be shown a prompt, click yes on it to complete the deletion.

Step 5: Reboot your computer and boot in normal mode.

The ESET Smart Security or NOD32 application should now be deleted, you can install a newer version of the software or install another Antivirus software with ease.