You could try enabling the mac filtering. For starters add your computers address and the psp. If this fixes it then add the macs of the other computers on the network if any.
Look around the wireless options and see if you can find anything about 802.11b and g. If you see it is in only g, then change it to mixed mode and restart your router if it doesnt do it automatically. Then try adding a new connection to your psp again.
Crap! I just reformatted on of my hardrives without backing up so very important files. Its a fresh windows xp ntfs install, I did quick format. These are memories that I can never get back, so is there any program that can retrieve them for me?
Although I prefer amd of intel, I think that video is extremely biased. Wouldn't doubt it if amd ran those tests as many times as it took for their processor to benchmark the best.