Please help! Internet doesn't work

[minsyoo]

Hi,

My internet has stopped working!
I have high speed internet and it's been problematic (i've had service for the past 3 weeks). and finally, it just gave out and no longer works. i called the internet provider and spent a couple hours on the phone with tech support and they determined it was the computer. which seems to be true, because i plug the internet to my laptop and it works fine and that's how im online right now. but i travel a lot and my family needs the desktop to work. So here's the situation...

the desktop (windows vista) can't seem to connect to the network. after taking some steps to troubleshoot, tech support has figured out that it's because my "Default Gateway IP address" is incorrect and is not receiving the correct information from the modem. So when i go to network and sharing center, view status (of local area connetion), and go to details, the ipv4 ip address and what not are all correct except the default gateway. it's showing a completely different address and the tech support said he could not figure out why, and it would be a problem with the computer. After i got off the phone, i tried to "manually set" the IP addresses and what not thru properties instead of "automatically get settings" Then it worked for about 3 minutes, and the internet cut out, since then, when i go to "network sharing center - view stauts - details" it actually doesn't even show an address at all for "default gateway" and at the top, it doesnt show that it's connected to the modem. (it says the name of the modem/network at top)

now, here's my speculation.

I have a VOIP phone, and it came with a.. i guess you can call it a router. so the internet cable from the modem goes into this "router" then another cable out of it into the computer. and when i had set it up, it wouldn't work. so i just unplugged it and set the phone itself on our wifi network and it seems to work fine. but im guessing that the "default gateway" address that the guy on tech support didn't recognize is an address from that...

ANY SUGGESTIONS? ADVICE? is there a way to "reset" ALL your internet settings so everything goes away and i can set it up again from the beginning like it's a new computer? if not a way to fix this problem? PLEASE HELP!!!!!

[Force Flow]

Please list out what networking equipment you have (brands & models) and how you have them connected.

Are you using Cable or DSL?

What VOIP provider are you using?

[minsyoo]

I have a 2WIRE modem? I'm in canada, and i use Telus. im pretty sure it's dsl. the voip provider is LG070... it's a korean provider, but i no longer have that device plugged in