Problems with wireless connection in WR850GP

Hi folks!

I have a motorola WR850GP conected in an ADSL modem to acces the internet, and I have my computer wire connected to this router and my Sisters comp. wireless connected.
So the problem is:
1- I can't see the sharede folders on her comp. and she can't use the printer on mine.
2- She is going to kill me because she is can't connect her MSN Messenger (when i use the messenger to test the tcp it says that its ok and i can connect to the service, but when i try to connect it says that could not connect to passsport).
In my computer i can use the messenger normaly, so i belive that the problem is in the configuration of the router, but not in the networking panel, i belive it's in the wireless config.


Someone please help me before it's too late, and i got murdered by my sister.

THKS.