If has os 10 could be power pc or intel as came in half way through,if power pc you can get office for mac older version,if intel you can run boot camp and install windows on a partion of hard drive so have both,or go in to parallels and run both side by side,but if you run a virtul machine within a machine it will slow things down,for ease run parallels so can work with both at same time,for faster operating then use bootcamp and boot to what you need at each time [windows or os]but both have draw backs as you have to decide what volume you want to boot to with boot camp and parallels working machne inside machine will slow things down.Beef up ram!
Adivce leave windows to your pc that you have lying around and just enjoy os for what it is,buy a book,and get going ;=D