OK, got another AMD 64 dvd image downloaded, and completed installation about seven hours ago. There were several minor hangups, but I'd been able to get past everything to the point where I thought I would experiment with net booting my laptop. DHCP found the boot location instantly and the laptop started downloading and installing (to ram?) the software needed, but got hung up after about five minutes. During this time, I had been trying to cure another problem by redoing the 'display res and sound' wizard on my hybrid/core which I had no idea would reload the core, let alone reboot the entire machine. The laptop seemed to take it in stride and tried to reconnect to the server, but it kept timing out. I let it sit for ten or so minutes before trying to jar it, but finally relented and hard powered it down. I had to run out the door on an errand for about an hour and briefly noticed that another computer on the internal network was showing a 'could not connect to server' page in firefox, but thought nothing of it.
Fast forward an hour later (five hours ago) and I tried net booting the laptop again, but this time it didn't find any DHCP. My first thought was a bad cord but I ruled that out, second thought was that my old wireless router (which I'd made static and was using as a switch) had locked up but I disproved that by connecting to its config page.
Five hours of HBOKing later, and here's where I'm at: The only NIC on the hybrid/core that is talking to any other machines at all now (old router, modem, internal computers etc) is the one integrated into the motherboard. I've tried three different PCI NICs, at least two of which were working just fine today even, and I can't get a peep out of them. This means that I have the choice of either an internal network, or an external network - not both. I've literally 'swapped interfaces' more than twenty times, coupled with every possible combination of powering down hardware in different orders and trying each configuration both ways (connecting integrated NIC to internal network and PCI to external, testing, then swapping them both without touching other settings). I've even isolated the internal network down to the hybrid/core, a crossover cable, and one other computer. The other computer can't even ping the PCI NICs! The oddest thing about this entire issue though, is that all three of the PCI NICs that I've tried have shown good link lights on themselves and and the other computer's NICs.
Here's a pretty common display in Advanced | Network settings ... notice the lack of a MAC address on 'internal' (currently set to the PCI NIC)
The closest thing I have to a working theory about what's happened is that the 'display res and sound' wizard somehow has control of the NICs too. I'm guessing that my first PCI NIC (internal network) was old and failed when I was attempting to net boot, and the system ignored it when I started the wizard one or two minutes later, and treated the setup as one NIC with two IPs spoofed. If that is in fact the case, I have tried everything in my power short of wiping and reinstalling to correct the error - I've even exactly duplicated the events surrounding the wizard, but with a known good NIC, and reran the wizard. All this though, to no avail.
I'm going to give one more go at it tomorrow before completely reinstalling. Any ideas out there on anything else I should be looking into, or something that I'm not comprehending?
P.S. hardware problems and software problems can be annoying, but when they're both happening at the same time, it makes you want to throw you computer out the closest window ;-) (Though there still lies the possibility that this is entirely software related.)