Hi desertboat1964,

Dell has not tested this system with Windows 7. However, you may try installing Windows Vista 64bit drivers in compatibility mode and see if it helps. You may download the desired driver from Here -> Enter Service Tag -> Select OS Windows Vista 64 bit -> Expand Modem/Communications -> Download the desired driver. You may follow the steps below to install the downloaded driver in compatibility mode :

• Right Click the driver installation file and select Properties -- > Compatibility Tab
• Select Windows Vista Service Pack 2 from the list in the following image.  
  
  
  
  

• Click Apply -- > OK
• Right Click the file and select the Run As Administrator option to install.
• Follow the on screen instructions and restart the system after the installation.

If the issue persists, please share the model number of device you wish to install. If you are not aware of the modem model number, you may follow the steps below and share the Hardware ID of unknown device in Device Manager : 

• Press Windows + R button on keyboard
• Type 'devmgmt.msc' (without quotes) and press Enter
• Check if you have any bang marks infront of devices
• You may right click the device under Device Manager and click on Properties -> Details -> Hardware Id

Please share a screenshot of device manager and hardware ids. Will take it further.