You can download the Sony Library software directly from
here. After installing the software and connecting your Reader via the usb cable, you will probably need to create an account and register the Reader to your account. If the Reader was registered by the previous owner then you will need to de-register it from their account first. Go to "My Account" and you should find information on how to do this.
Any wall charger that plugs into the usb port on the Reader will not work. A wall charger must plug into the round, yellow port on the bottom of the Reader. Any PSP wall charger will work for charging the Reader. It will charge from the USB port on the computer but the computer must be turned on and not in hibernate mode. I use a retractable cable similar to
this. It is smaller than the normal PSP charging brick.
Good luck with your find and hopes it works better for you than the Nook.