Networked computer, suddenly has not internet connection .

Hello all and thank you in advance for any information and help that you may be able to give me

We have been running a home network for a while now.

Both computers are running Xp and are connected using two lan cards.

I can see the secondary computer using the network but they cannot access the internet.

They have the limited or no activity icon.

After reformatting the secondary computer I still receive the limited internet icon on thte secondary computer but I also see the icon on my “outgoing” lan card.

can anyone give me any hints on where to start?

Kindest regards
Hayley