Ok there is too much confusion in here and let me start up from scratch so thats it easy to understand the concept .well ill refer the 800 mhz p3 as PC1 and the AMD as pc2 .First .. on the first NIC of the pc1 1st network adapter (assuming that its the adaptor with which the dsl is connected) assign all the information which your ISP provided (default gateway , dns servers , secondary dns server ,WINS forward loockup if any

) and on the second nic assisgn a static ip address , for example 192.168.0.1 and a subnet mask of 255.255.255.0 .Assuming that this is the network with which the pc2 is connected with .no default gateway is required in this NIC.On the pc2 , assign a static ip of 192.168.0.2 with default gateway of 192.168.0.1 and a subnet mask of 255.255.255.0 .Make sure that you have assigned a static ip , and not DHCP , cause if you use that , ip's take a lot of time to be refreshed and may slow the system down.This config normally works and hope this helps .