Connectivity Issu

Hey!
This is the story- Last week on Thursday when the demo of COD4 was released I was getting really low download speeds. As a result I disabled my LAN network which connects the other computer in the house to the internet, thinking that my dl speed would be higher. I saw I was wrong and re-enabled the connection.

For a couple of days later the internet on that computer was acting funny. Internet based programs like Skype, MSN or ICQ would work, but no pages would load in the web browsers if IE or FF. Today I decided I'll try and figure out the prob. This PC is using Vista (the other is XP Pro) so I pressed diagnose on the LAN connection and it told me I had a problem with the LAN's IP address. I opened up Windows Help where they said that I should make sure the IPv4 is in correctly, if specifically or automatically. Mine apparently had a specific one, so I thought going to automatic would fix the porb. Unfortunately it might have made the situation more difficult because I get a message that the automatic IP address is no good and I didn't wright down the specific one.

Does anyone know what I should do? I don't believe that the specific IP came directly from my ISP because I upgraded and re-formated both PCs several time and never had to manually configure anything.

Help please?

I am not running a router. My main Vista PC connected to the internet view a DSL modem and then a wire connects both PCs via the ethernet. Vista has been doing funny things with the internet like it randomly not working even though it says it's connected. But I don't know if this is a similar situation. I'd also like to add that the LAN network shows me that it's connected to Local only- no internet for some reason.

I've also tried taking the IP address from the main connection on the Vista based PC and implanting that in the LAN network. When I do this on the Vista PC it says that the network is connected but I still can't really connect to the internet.

Suggestions?

I tried calling my ISP yesterday and they told me that they don't deal with home network issues such as mine. Unfortunately I don't have or know anyone with a notebook to test out.

I was thinking that maybe if I download a different ethernet driver things might clear up. Could this even be a driver issue? Would getting a different help?