The fact that you have to run as administrator for Manager to work sounds like you installed Manager to either the program files folder, windows folder or other folders that require admin rights to change files within that folder when you are running the program.
Backup your data, remove Manager in add/remove, then delete the Manager folder (find that first before you uninstall Manager). Lastly delete any references to Manager in the registry by deleting the keys, not just the values… Look for NgSoftware in the registry.
Reboot the pc and re-install manager and make sure that you install it to a non admin location. I usually create a folder called c:\manager and install it there as I have never liked Manager running from the users appdata folder. Although in this case, it sounds like Manager is running from the programdata or program files or windows folder if it is requiring admin permissions to run.