First things first -
DO NOT just delete Kontakt (or any other Windows program, for that matter) without first trying to run the uninstaller first!
Deleting a program folder without running the uninstaller first can lead to all kinds of run-time errors!
If you can't find a Kontakt folder in your start menu "programs" menu, check the "Programs..." app in control panel, and if Kontakt shows up, uninstall from there. I also recommend rebooting after uninstalling apps to give Windows a chance to make a "fresh start".
Although for some reason you have had issues with your installation, I think you'll find that in general, the entire Native Instruments Komplete suite is very reliable, and generally the Service Center does a pretty good job of managing updates. There are a few hiccups for some folks now and then, but I think you'll find they are the exception, instead of the norm.
I started with Komplete 8 on a Windows 7 PC, ran it on Windows 8.1 and Windows 10, and just recently cross-graded to Komplete 10 - and threw in Komplete Select and several other NI and 3rd-party libraries along the way. In all that time, I thing I've only had to take care of Service Center hiccups maybe twice, and in both cases they were corrected by manually running the updates, as I mentioned earlier.
If you do reinstall Kontakt, I recommend you "take charge" of the installation process, and install all your libraries in a separate folder that is easy to find and monitor. This will make it MUCH easier to deal with any libraries that need to be added manually, or if you have to deal with missing samples or other related issues down the road. Also, recommend you get the factory Kontakt installation working properly first, with all Service Center updates, before adding in any third-party libraries.
As far as your initial Kontakt installation files are concerned -
You can download any purchased NI programs and libraries - and all the latest updates - at anytime by logging in to your account on the Native Instruments web site. So, if you have a problem with your backup set, a fresh copy is readily available for the download.
I'm not familiar with the library you plan to add, but if it is one that has to be manually added (i.e., doesn't show up as an instrument in the Kontakt browser window), it's fairly easy to add it to the Kontakt Quick Load menu - Google and YouTube can show you the way!
Good Luck, and don't give up -
I think you'll find that once you get past these initial unusual hiccups, Kontakt is a VERY nice sampler, with a HUGE library available (from NI and elsewhere online) to add to its potential.
Randy