Lan Internet Connection Problem???

[twix3]

I have the Soyo SY-K7VME with the on board Lan Port and a Athlon XP 2600, i installed windows XP Professional and i cannot get the internet to work properly. I have a Speedstream 5036 DSL modem and a 4060 USB Dsl Modem(not hooked up at the same time obviously). Here's what happens, i setup up my interent but my LAN connection keeps going dead and my DSL light keeps turning off on the modem and the modem flashes as if it was reset. i went ahead and plugged in my old HP 1.0 GHZ Celeron computer with the same cables, modem, and everything and the internet works fine so it wasnt my provider or my modems. i then decided to hook up my ethernet card from my old computer and install the proper drivers same thing. So i then decide to setup up my USB Modem and the same thing occurs but my connection stays connected a little bit longer. so i've checked the modem, checked the drivers, checked my internet provider(also boggled the minds of there tech department) and i tested all the hardware. i dont know if there is something i need to set on my motherboard or if the motherboard itself is screwed up or even if its some sort of power supply issue. I tried eveything on the soyo tech support page and still no avail. if anyone knows what i can do please let me know? the only other thing connected is my AGP Radeon 9600SE Video Card(if that deos anything)