Web server network problems

[rmnwc555]

One of our web servers is having network connectivity problems. We lose internet connectivity intermittently, but still have an internet connection 60 - 70% of the time. Our 2nd web server is working ok, when we turn off load balancing and just use our 2nd web server. It looks like it might be an NIC problem which are integrated into the motherboard. Each server has two NICs, and both NIC connections are giving the same problem on the first web server, which seems kind of wierd. We are going to try an external card in one of the empty slots to test the connection and see if that works. We are also going to see if it might be a software/driver issue. Our other web server is the same hardware and configured the same, and working fine. We have not made any changes or updates to either of these servers prior to the problem. Wanted to see if anyone has some idea of what else it might be.

Here is our configuration:

-SuperMicro X5DPA-TG server

-Microprocessor: Dual Intel Pentium III microprocessors with an internal operating frequency of 3.2 GHz

-System bus: 533MHz/400MHz

-Expansion slots: 5x 32-bit 33 MHz PCI (5V) slots

-Memory: 4 DIMM 72-bit 184-pin sockets

-DIMM capacities: 1 GB registered ECC SDRAM

-75GB drive

-Running Windows Server 2003, Web Edition