1.go to control panel --- network connections click on wirelss network it will b enabled ..first check out your wireless adapotor in your laptop is turned on..

2.if you are getting very low signal ..i prefer you to use alfa one wirelss router.. it works very nicely man..

3.conect to some other internet providers go to website of your laptop name n model number download wireless network driver..
once it is downloaded run it..disconect n try with your wireless connection.. im sure it will work..