PS2 Network Adaptor w/DSL troubleFollow

Well, I got the PS2 Network Adaptor the December after it came out, and it has been gathering dust on the back of my PS2 pretty much ever since. I set it all up correctly, and I can actually play on the internet on my PS2... but, once everything is set up the internet connection on my PC goes down the drain... which is a pretty serious problem considering how much my household uses the comp. =p

I have tried it several times, and followed the instructions exactly for both the router and the adaptor, but the same problem always comes up. The internet pretty much becomes unusable on the computer.

Oh yeah, I'm not using wireless. Has anyone else had this problem, or heard of it? It's really bugging me since so many online games are coming out and I've always wanted to play FFXI on the PS2.