thanks the problem seems fixed now. I did a system restore and it started working again.If it won't work at all using the installed WiFi then you may well have a damaged part. It happens.
If the laptop is under warranty I would contact them about a repair. If it isn't under warranty then you can either try replacing the part yourself (if you feel comfortable doing the work), take it to a local tech to do the work, or use an external WiFi that connects via the computers USB port.