BleepingComputer.com: IPConfig returns a DNS Suffix of Not Valid

First of all I want to say what a great site you all have put together here. The list goes on and on of tremendous help you guys (and gals) have given out. First time posting so here goes. I am working on a friends Desk Top that is running WinXP (SP3) and has all the current up dates validated and installed. It did have a couple trogens loaded and some malware and by following along some of these other issues on here it seems to be free so far. the one issue that is still resolved is that I am trying to set up a wireless network for him and his family but when I do an IPConfig it returns a DNS Suffix code of Not valid. the local area connector returns a random IP address each time. And the wireless router maintains it's DHCP enabled IPAddress. The modem is a DSL and is plugged into the desktop via a cat5e cable. Now I believe my mom has the same cable company (and the same DSL modem) and she recently lost service because I think SBC Global switched to AT&T. I think all I did was go to the AT$T website and download a few quick downloads and it was off and running. My friend doesn't have his email adress or PW anymore to boot. My question is, is this a HiJack DNS? or is it more of a setup issue with the modem? Sorry I am not near the desktop but wanted to get this out here. I can provide all the logs and test tonight/tomorrow night once I get back over there to look at it. But I believe his Desktop is set up right.... Let me know when one of you get a chance! Thanks!

What happens if you set a Static IP address?