Problem connecting to router (Wirelessely)

Hello,

I have HP with in built wireless.
When i try to connect to the router wirelessely, inspite showing strong strength it does not connect.
it alwas shows acquring address bt at the end of the day back to zero.

i tried by giving manual ip to my laptop however it does get connected but i cant browse the web despite showing connected.

rest of the other laptop gets connected.

when i connect with LAN cable, it works absolutely fine..

ne idea y m i not able to get connected with my router which is connected to the desktop pc (Server)??

Thanx