My Sony vaio laptop won't connect to wifi?

it swiss no Internet connection and then troubleshoot option and doesnt work.. can someone please help me..

Sony Vaio EB4X0E/BQ Intel Core i5-480M 2.66GHz 4GB RAM 500GB HDD Laptop

Sony Vaio S13L8E/B Notebook Dual-Core Intel Core i3 3 MB 320 GB SATA With 0.3 Mega pixel Camera

SONY VAIO EB Series VPCEB44FX/WI Notebook Intel Core i3 380M(2.53GHz) 15.5" 4GB Memory DDR3 1066 500GB HDD