internet protocol annoying thing

I just recently changed high speed internet service providers. Since the moment that I changed, I have had to manualy reset the "obtain an ip address automatically" in the internet protocol by putting in a fake ip addy, closing, opening, and then setting it to "obtain....automatically". It took me a couple hours of fiddling before I figured this out that day...and now I am stumped as to why I have to do this everytime I turn on the computer.

I have updated the driver, uninstalled the driver..and did a bunch of nothings in dos (purged dns...yadda yadda).

I am running XP Pro. With both providers I never installed any software. And , I did everything in the "How to: Spyware, Trojan And Virus Removal", then I ran Hijack This and compared it to the tutorial.

I'm posting this in hardware and software because I'm not sure if it is a problem with the hardware, or if it is software. Any help would be appreciated