Try the steps below if you still have an issue with your Navigator you can contact the support desk it may be a Hardware issue.
http://www.3dconnexion.com/support/tech_support.php
Full uninstall and reinstall process for Windows XP, Windows XP 64, Windows Vista 32 and Vista 64:
Before proceeding make sure they or their IT administrator are logged in with full admin privileges.
1) Download the latest driver from the 3DConnexion website and save it to an easy to access location such as the desktop.
2) Uninstall the current driver through the Add/Remove programs. Then make sure the 3DConnexion folder in C:\Program Files is deleted and purged from the Recycle Bin.
3) Navigate to C:/Documents and Settings/your profile/Application Data or C:/Documents and Settings/admin/Application Data/ and delete the 3DConnexion folder there and be sure that it is also purged from the Recycle Bin. Check both locations to be sure.
NOTE: on Vista machines the paths to the profiles will be found in C:/Users/your profile/AppData or C:/Users/admin/AppData/.
4) Under the 'Start' button and 'Run' type in 'regedit' and hit OK to bring up the Registry Editor. It is strongly recommended that a backup of the registry be made first by right clicking on the My Computer icon in the left panel of the Registry Editor and selecting 'export'. Title it something like Registry Backup and point it to an easy to access location like the desktop. Once the backup is complete there are 2 registry entries to remove:
Under the branches