iMac 5,1 won't connect to internet over WIFI. Running Tiger, HELP!

Ok so since I bought I laptop I moved my iMac 5,1 into my kids room. I had leopard on it but it always had buggy issues so I went back to running tiger. Literally hours before when it had leopard everything worked fine. (On the internet).
Since I reverted back, the mac will not connect over WIFI. I am absolutely sure I typed in the correct password but it will keep saying password not correct for airport. Or simply it would not connect. The password issue is weird though since I actually changed it, reconnected my laptop and iPhone with the new password and I get online. Any suggestions?

I guess its all worth a try. Ill go into my settings and try to change the password types.

Ok changing to WPA WORKED! THANKS! I was online. But.....
after a restart I get this lovely message at the welcome screen.
Im getting frustrated!

Stooby Mcdoobie said:

Are you on a fresh install of OS X?

Click to expand...

Yup. Freezes after some use. Gotta keep restarting. I installed some new RAM and it still freezes after some use. Looked up the issues and it seems to be a logic board issue with those iMacs. No real fix really. Most people installed SMC to run the fans more. Puts a band aid on a bigger issue it looks like Apple ignored. heres a link http://www.youtube.com/watch?v=viaVumyro3o ohwell.