Start by opening the Control Panel.
To get to the control panel, click on the start button.
On the right hand side of the menu, find "Control Panel" and click on that.
With Control Panel open, click "View network status and tasks".
Next click "Manage Wireless Networks" link on the left.
Right click on your wireless network and select "Properties" from the pop up menu.
A box should open with two tabs at top. One labeled "Connection" and the other "Security".
In that box, you should see "Network security key". If it's all dots, check the "show characters" box below it.
Be very careful not to change this security key by mistake.
This security key is your wireless password.
Please let me know if this worked for you or if you need further assistance.