If the Wi-Fi light is orange then the card is not active and will need
a driver. Most likely cause is a Broadcom chipset Wi-Fi card and the
way around that is to connect the laptop with an ethernet cable to the
router then get all the Ubuntu updates plus hardware drivers that way.
Ubuntu will automatically start these updates but you can always fire
them up manually by going to [ System / Administration ] then clicking
on either 'Hardware Drivers' or 'Update Manager'.