Have you tried updating the wireless card drivers? Also is the router running the latest firmware ?

Actually nothing wrong w/ my router because i had another laptop connect to this router just fine.  I went out bought the usb wireless card.  after installed it.  The new card got worser than the card came w/ machine.  it can not dectected my router.  i thought something wrong w/ the card.  i went to exchange another it same problem.  it is possible this computer had problem.  i really don't know at all.  thanks for reply my message.