WiFi issues

I have a 1st gen iPod touch. It has worked great up until a few weeks ago when I upgraded to the 3.1.3 OS. My iPod will find my network (wpa protected) and asks for the password but when I put the password in it comes up with unable to join___network. If I take off WPA it will connect but it won't stay connected, so like every time I get on the internet it will disconnect. I've tried resetting network settings, I've restored it, I've even gotten a new router. Anyone have an idea what I can do to solve this?

I have a similar problem with IPOD touch 3rd gen. I changed my router security to WPA and tried to connect to internet and it asked for the passphrase. I put it in and still wouldn't let me join.
Hope someone can help us.

I luckily solved my problem. I reset my network settings to factory default and it found the network immediately and did not ask for any further passwords or proof.
I don't know if you have already tried this, but it is worth a shot if you haven't.
Good Luck