I have a 2 yo computer, custom ASRock G31M-S R2.0 with XP. I have QWest PK5000 wireless modem. I do not have a wireless computer, have a desktop. I am connected to the Internet by Century Link. The ethernet light doesn't stay on, and therefore I lose my connection to the internet. Sometimes for days at a time. Everything is plugged in. I looked at the wires outside my house to the area where my computer is located. Looks good. Century link says it is my computer. I don't have a clue what could be wrong. I thought it was fixed, for a time the Help & Support on my computer wasn't working, but I repaired that today, thanks to Tom's Hardware help. What can I do to keep my connection to the internet? I connect to the internet with Explorer, and I have Yahoo!
IMO if the light on your router which indicates a internet connection isn't even on; then you need to contact your ISP and have them issue you a new router and a technician can come to your home and check out your connection.
They have specialized diagnostic equipment to identify whether the issue is your computer or their network/hardware.