Hi Sinead and welcome.
It will depend on which password is being asked for. There may, or may not, be a BIOS password set - if this is set then the Vaio will ask for it immediately it is turned on. To get a 'one-time' BIOS Password reset, you will need to telephone Sony Support who can give you a code over the phone. They may ask a few questions to help show your entitlement to the Vaio.
Most people do not set a BIOS Password however, and it is more likely to be the Windows OS Password that is needed. If this is the case the Vaio will begin to load Windows, the screen colour will change and you will be asked for a User Password. You will probably need to know which version of Windows is running on the Vaio and Google will give you several alternative methods of password recovery depending on if you have a Windows installation disc or not.
Google for "Windows Password Reset"
If you need help, please come back and ask!
