I am having trouble w/networking

[rookie2linux]

Hi,
I am relativity new to ubuntu.. I have an old distro 8.04Lts which work fine but when I upgrade to to 10.04.3 LTS it takes a while and will work but all of a sudden my internet just stops working ... I am wired into a wireless router.. and after I upgrade to 10.04 it works fine and all of sudden it stops and instead of the up and down arrows I see the wireless symbol. and I'm not sure how to get the mac address. plz help it is aggravating b/c i have to upgrade the long way and for my net to stop working it is just aggraviting altogether.
thx
Dom

[HalfNote5]

Just a thought, is the wifi card in the laptop also configured to connect to the same router?

In my experience, a lappy usually doesn't like being connected to the same network twice, unless you're going to manually configure one of the cards. (Oh, it WORKS, but depending on the hardware/OS it can be sort of clunky.)

Does it work better if you disable the wifi card on the machine? Or do the problems still persist?

Edit: I say "laptop" because you mention the wireless symbol, and most desktops aren't equipped with wifi by default. The point still stands if it IS a desktop, but I didn't want to simply ASSUME it was a laptop.)