If you uninstalled NX10, ( -why ?) the uninstaller probably, as Cowski notes , removed the windows system variable SPLM_LICENSE_SERVER.
But, if the directions from Ehaviv cured the issue. keep.
If your intention is to keep NX9 but not NX10, you should not do anything more with the license server.
Regarding the "uninstalled NX10", it is very common that the uninstaller leaves a few files and directories.
Select the NX10 folder - "Properties", a NX10 install is somewhere between 10 and 30 GB, between 100 000 and 250 000 files.
( dependent on what is installed )
If there are say 500 files/folders in the NX10 folder, the uninstaller finished as expected. You can / need to manually delete the remaining.
Regards,
/ Tomas