Running Wdws7 pro on two new Dell XPS. I back up all of my information on my ACER Aspire server.

 I back up all of my information on my ACER Aspire server. The new Dells with the Wdws 7 pro will not find the server. It will find the server for backing everything up, but when it come time to retrieve the material it will not find the server. I also have a backup server with Wdws 11, it will find the Acer server, so there has to be something either with the Dell, or a combination of the software and the laptop.
Have this problem only since the purchase of the new laptops. My old XPS, never had any problems using Wdws XP. Either this problem is unique, for either no one wants to venture a solution, or either Dell or Microsoft have a glitch no one has encountered.