Before you rent or buy any equipment, you ought to determine if you should be sanding and refinishing, or screening and refinishing.
Read the FAQ (Frequently Asked Questions) on this WEB page, Some Hardwood Floor FAQs, and decide which to do. Remember, the floor can only be resanded down to the 'tongue'. If you know that it's been SANDED and REFINISHED 2-3 times, you may not be able to do it again.
Read the entire FAQ page, top to bottom. It helps to give you a much broader picture of what you're in for. My best to ya and hope this helps.