You do not mention whether the two computers are using a wireless or an Ethernet connection, if wireless I would start by connecting the wife`s notebook direct to the Ethernet and see how that goes, please make sure that the drivers for the Ethernet device are installed before doing this.
For your desktop can you do the following;
Download then run Speccy (free) and post the resultant url for us, details here, this will provide us with information about your computer hardware + any software that you have installed that may explain the present issue/s.
To publish a Speccy profile to the Web:
In Speccy, click File, and then click Publish Snapshot.
In the Publish Snapshot dialog box, click Yes to enable Speccy to proceed.
Speccy publishes the profile and displays a second Publish Snapshot. You can open the URL in your default browser, copy it to the clipboard, or close the dialog box.