Hello,

1.Radmin VPN won`t work if you use Windows XP x64.
2.If you use other OS, try this:
https://support.microsoft.com/en-gb/help/834484/you-receive-an-error-1603-a-fatal-error-occurred-dur...
3.If you have an installation problem, try this:
https://support.microsoft.com/en-gb/help/17588/windows-fix-problems-that-block-programs-being-instal...
4.If you get an error "Network Resource That is Unavailable", use this manual:
https://appuals.com/fix-the-feature-you-are-trying-to-use-in-on-a-network-resource-that-is-unavailab...
5. You can also try this:
https://support.radmin.com/index.php/Knowledgebase/Article/View/106/12/Radmin-installation-fails-or-...
6. If you can`t install or uninstall, try this
Microsoft Program Install and Uninstall Troubleshooter
https://support.microsoft.com/ru-ru/help/17588/windows-fix-problems-that-block-programs-being-instal...
7.If you have problems to uninstall Radmin VPN, you need to use MIcrosoft utility.
1. Download this utility https://support.microsoft.com/en-us/topic/fix-problems-that-block-programs-from-being-installed-or-r... and run it.
2. Press Next и choose Uninstalling.
3. Find Radmin VPN  in the list and press Next.
4. Wait till the utility completes uninstallation and reboot your PC.