First follow all suggested previous advice.
Next, the mac address cannot change on the card, it is permanent, unless the chip became toast, it is a permanent part of all network cards.
I know you've triple checked all your software setting's, do it again just incase, sometime's thing's look the same after staring at them for awhile.
I have RR, so your's may not be the same, your ISP may actually use static #'s for your network settings. When in network settings, click the TCP/IP, and look at it's properties ( you do have TCP/IP installed don't you?

)
On my Ip address tab, obtain IP automatically is checked, they give it to me dynamically. On the WINS tab, disable WINS resolution is checked. This setting may or may not apply to you, most likely it doesn't.
On the Gateway tab, I do not have to enter anything, you may have to, but that would be specified by your ISP, and should be readily available on their web site for configuration.
On to the DNS tab, here mine is disabled also. Again, these settings would be specified by your ISP, but is unlikely they use this either.
Try to ping yourself, to see if you at least get a response. Open a command prompt, and type in " ping 127.0.0.1 " , of course without the quote's. You should get a ping time.
If all else fail's, commandeer your roommate's computer, go to their web site, and see what you can find, or as a last resort, call " tech support" and see if they can get you going. If not, more settings info may be necessary.
HTH, and good luck.
Oh yeah, forgot to mention double checking for IRQ conflicts, still think it would try and make some attempt to connect though. But ya never know.
[Edited by Skinny Boy on 03-15-2001 at 12:41 AM]