Hey herbz100! Welcome to G2G!
Kind of a little curious as to your problem at hand.
You say that you are having troubles copying files from your computer to your external HD, but then you comment that you can use the Internet fine for about 1-2 hours before it hangs up on you. Sorry but just kind of confused about what is going on. If you could, please answer the following questions the best you can:
1.) Are you using the Internet when you are copying files to your external HD?
2.) Have you tried having nothing plugged into any of your ports besides the Ethernet cable for the Internet (and maybe a mouse/keyboard)? If so, does the problem still occur 1-2 hours later?
3.) What type of Internet connection do you have? I.E. -- Cable or DSL or Dialup
4.) What do you all have plugged into all your ports? (mouse, keyboard, camera, etc.)
5.) You say every port stops working, so am I safe to assume that you mean you no longer can use your keyboard and mouse, and that you have to manually power the computer down? If not, then what does work, and what doesn't work?
Once you answer those questions, we can proceed and see if we can't figure this out.