Wifi switch not working

Hello,

I have an Inspiron 1525 that my father in law bought for my daughter off ebay and I can't seem to get the wifi to turn on.  I tried going into the bios to turn off the switch but I can't change the settings because I don't know the admin password.  I asked my father in law for some kind of proof of purchase but he said ebay doesn't have a record of it anymore since it was purchased several years ago.  What can I do?