Q: Mini Losing WiFi / Internet after a few hours

Hello all, I have a Mini that is about 18mos old, and as long as I can remember I have had this issue, I had attributed it to my AP, but I have since moved and using a different AP and even a different ISP.  After a couple of hours, the Mini will lose network connection, most of the time it shows connected to the WiFi network, but cannot get to the internet or any other devices on the WLAN - other devices on the WLAN do not ever have this issue, including iphones, ipad, MacBook Air, AppleTV, and w32 laptops.  Occasionally it will just drop the connection to the WLAN, despite the remember/auto connect being set for the WLAN network.  There is no effect on if the machine sleeps or not, I can be in the middle of using it and this will happen, I even tested leaving an app that uses internet traffic open to see if it would stay up if there was traffic, and it will not.  Turning off/on wifi resolves the issue when its connected to the WLAN but not working, clicking on the SSID in available networks resolves if it just drops the network.  That fix is fine if I am home, but it is a community computer and the wife and kids are NOT technically sound, so it dropping causes issues, along with the fact that I have LogMeIn installed so I can grab stuff while Im at work.

As mentioned, this has happened in multiple locations, with multiple APs and ISPs, and other devices never have this issue.  I believe the Mini has 10.7 on it, but I will have to verify, at worst it has 10.6.

APs have both been non-apple (one Belkin, one offbrand provided by ISP) - The APs work fine, as this issue does NOT appear on the MacBook, and the issue has appeared on both APs.

ISPs have been Comcast/Xfinity and Consolidated Com.  Same as with AP, never issues with MacBook, always issues w Mini.

I have tried different physical locations to eliminate reception / interference, and it makes no impact.  In fact, the change in AP/ISP comes with a physical move to another house, so that should eliminate that.

This has to be a Mini issue as far as I can see, just a question of if its a HW/SW and what other thoughts there are to try resolving it.

Any thoughts are appreciated - just as a background, only been using Apple machines for about 2 years, but I have worked in IT for over 15, so I have a pretty good grasp for what to look for (I dont mention that to say I know what im talking about, only that I'm not a basic user that cant figure out where the power button is! )