please help me with my toshiba laptop

hi,
i have just bought a new Toshiba Satelite M205-s3217 with Windows Vista Home Premium.
i have a Lantech wireless router with me and when i try to connect the Laptop with the wireless it shows network connections are available but it does not connects. the error says please try reconnecting again
i tried to connect my router with my PDA and it connects. i tried to connect the PDA with Laptop through ADHOC connection it connects. but when i try to connect it with router through infrastucture connection it does not connect. it shows that the wireless connection is available for router but it does not connect.
i have tried using WEP key,Wpa Key and without any security as well but all is in vain. please do kindly help me
i am from Nepal and we do not have any toshiba retailer or service center or support center here.
please kindly help me
best regards
Ritesh