Desktop Wireless and Networking

I don't know if this is something that can be solved here. All I know is that my desktop seemed very fast when I first got it. Now, after several calls and service visits from AT&T, I'm wondering if something has happened to the desktop and not the WiFi service from AT&T. Just minutes ago I did a speed test on my desktop, and the same test on a laptop (also HP) and my desktop got 27 ms latency, 11.1 Mbps download speed, and 2.3 Mbps upload speed. The laptop using the same WiFi router got 26 ms latency, 28.2 Mbps download speed, and 12.74 Mbps upload speed. The AT&T guy earlier with the laptop connected to the router by wire was getting download speeds in the 50's I think. I guess I'm just looking for some ideas of what to check, add, remove, etc. that may fix the problem. Anything typical. As far as I know, the desktop is much better than the laptop, so the laptop shouldn't be winning in performance tests. I've had it for about two years now and use it everyday for work, etc. Others use it for games and video. I don't think it is overloaded or anything with programs or apps. I have McAfee protecting everything, and added Malwarebytes to get rid of everything else. Any ideas are very much appreciated. Thanks!!