Ok this is a strange question, but before I continue let me place a few specs down.

Network Adapter: Marvell Yukon 88E8001/8003/8010 PCI Gigabit adapter. (on motherboard)
Linux distro: Suse 10.0
Windows version: XP home

Problem:
I just installed Suse today on this machine and it worked great.. got everything running in about 16 minutes flat. Internet works GREAT in Linux and there are no problems whatsoever there, however my problem begins when I boot into Windows (which is on a seperate drive.. basically a dual boot here).

When I go into Windows, I find that the "network cable is unplugged" and the internet doesn't work. The lights on the adapter are off and there's basically no life at all.
I boot back into Linux and the adapter works fine!

It's definitely not a hardware issue here, and to settle any who don't believe, I've tried changing cables, changing RJ-45 ports in the wall, changing router ports, changing routers themselves, and it works in Linux!

Now I know what most of you will be thinking "Yeah well Linux is better anyway!" or "Figures it works for Linux and not Windows!" and yeah you're probably right.. but the problem only started after this Linux install, and I have a feeling the problem begins after the shutdown process. It's disabling the network adapter somehow so that Windows reads it as having the cable unplugged.

I did a quick search on this forum and came up with nothing.. any ideas?

EDIT: ANSWERED! -> I saw the answer in the related links below my post. People were having problems in Suse with the same network adapter! Turns out it was a driver issue afterall.. kinda funny that you have to download drivers for a network adapter that doesn't work.. luckily I'm a geek and so I have extra NICs laying around all over the place.

Don't have a direct link, but you can try going to http://marvell.com/drivers/

That does sound mysterious. Have you checked in 'device manager' in windows to see if a problem for the ethernet card is reported.

yeah I did.. Device manager says the device is working properly, nevertheless I tried disabling it, enabling it again, uninstalling it and reloading the driver to see if I could jump-start it.. The only problem that's reported is that the network cable is unplugged. Very mysterious indeed.

EDIT: I'm just wondering if there's some part of the shutdown process that could disable the card in such a way that windows doesn't detect it anymore.. Windows sees that it's plugged physically into the computer, but it's like the eth jack itself is turned off.

I'm new enough to linux that modem problems in general are tough. My hp pavilion came with win modem card installed and after searching the net for answers I gave up hope on using it.
I set up an old box with win 98 as that was all it could handle, and used it for a while as my internet machine and am trying as my spare time permits to get file sharing via either samba or ftp going between the boxes.
Then I thought about trying a proxy server on the windows box to see if I could get out on the net with the linux box through the win box as a proxy. And the good news is, it worked.
The proxy program is free but not open source and is called FreeProxy.
I had an instructor that had to put two modems in his computer: one for the windows partition and one for the linux.
Could linux adjust irq settings in the bios of the computer?

You could try to "lock" the IRQs in CMOS setup. How you do this may vary withe the m/b but essentially you assign an IRQ to a slot.

I've done it before when a sound card and a NIC kept on moving round in IRQ space but frankly cannot remember the details.

I suspect that Windows is causing the IRQ changes, if that is your problem.

Note that there are Linux distros which are small and designed to be a router/firewall on a low powered machine. A 386 would do.