I cant get the client to connect?!

I got a buffalo whr-g54s with a matching buffalo high speed pci card. I installed he router to my pc and installed the client card into a p3 downstairs (1 floor down). The signal jumps from low to excellent to good back down to low, and then all over again. But I never get less than about 40% signal downstairs. So i try to connect. I type in the wpa password and it goes up to the point where it tries to aquire an ip address. Then it just stops and says that it cant get the ip address . If it does connect, it says limited or no connectivity. funny, the first time i tried, it worked at 6000 kbps down and 1500 up on the client pc. then, it just stops. Now it wont connect at all. PLZ help me, this is just ridiculous.

I tried with WEP, WPA, and AOSS. None of them work, only wpa gets a good connection. In fact, the internet worked for 2 minutes at a time yesterday. Then it stops. I press repair. It works again for 2 mins. Really, it pisses me off.

I don't think its the security part. My router says that the client is authorized and authenticated as part of my wireless network.

lol, srry. Ill try it without security. Ill post results later.