Please,
Reinstall the package as usual and then disable the server:
# update-rc.d nxserver disable
Try to reboot and see if the login screen comes up.
After that, re-enable the server:
# update-rc.d nxserver enable
# /etc/NX/nxserver –startup
See if you can connect.
Disable all services by editing /usr/NX/etc/node.cfg and setting:
EnableDiskSharing key to ‘none’
EnablePrinterSharing key to ‘none’
EnableUSBSharing key to ‘none’
EnableNetworkSharing key to ‘none’
EnableSmartcardSharing key to ‘no’
But not disable the NX service.
Reboot.
See if without the services the login screen comes up.
Stop at any failed step and please send the logs.