Hi ,

I would suggest you to try these steps and advise the result .

*Delete the USB root hubs from the device manager ,restart the system and then check if the system detects the USB devices .

*Update the chipset and the USB drivers from dell support site .

*Check if these USB devices fail to work on any other USB port of the system .

I hope this helps ,but if there are any other queries then do reply to this post with the service tag of the system sent via private message .

Have a good day ! 

Regards ,