There are most probably 1 reason why you cannot connect to the internet via wifi.
1.) Your wifi driver(s) have been corrupted therefore not enabaling you to access the internet via wifi.
This means that your computer doesn't have the driver, (Which is a technical term for software), to access the internet via wifi, Wireless internet.
To fix this problem you will need to know the make, and model of you laptop/computer.
Thet's say you have a HP laptop... simply type into google, "HP" and there website should appear under the results. Be sure to click on the right one! (This is usally the top 5 results)
On HP's website there will be a tab in the top right hand corner saying "Support and Drivers". Click Here.
Then type in the model of your laptop. Eg. NX6125
Then click on "Download Drivers and Software". This should bring up another page.
This is the important part: If you have windows Vista (the type of operating system) be sure to click on vista. If you have Windows XP Professional be sure to click on XP professional, and so on.
Again, This should bring up another page.
Then Click on the hyperlink: "Driver - Network" - This simply takes you down the page...
Then download ALL of the drivers under network...
To install them, simple click on the file in downloads in my documents after fully downloading...
I hope you found this review helpful...