Packard Bell Legend 300 cd, 60mhz: will it work with usb card?

My Freind has a Packard Bell Legend 300 cd,60mhz that he will not give up. I am supposed to back it up weekly but it doesn’t have a usb port. Can I safely install a two port usb card in his machine without burning it up? The data on his machine really is irreplaceable.
Paul
paulnkathy@hotmail.com