Hi Jim,
Please follow the below mentioned steps to isolate the issue:
- Disconnect all the external devices except the keyboard, mouse and monitor, then power on the computer.
- Disconnect the power cable from the computer.
- Press and hold the power button for 10-15 seconds to remove the residual power.
- Connect the power cable back to the computer and then power on the computer and check.
- We can also check if the issue occurs in Safe Mode with Networking. Refer to the link to boot the computer to Safe mode with networking: http://dell.to/LnNtve
- To check the BIOS version currently installed on your computer, click Start-> In search Type “msinfo32” -> press Enter.
If issue persists, then run the online diagnostics (Choose a Diagnostic Type as components) on the computer to check if the hardware (Network card) is working fine.
Please perform the steps mentioned above and post the results.