Good Computer for Playing Nancy Drew Games?

I basically want a desktop that I can install Microsoft Office and the Nancy Drew games on. I would like it to be under $500 (if that's possible), and it has to have enough hard drive space to be able to have all the Nancy Drew installed on it. I basically know nothing about computers so help would be appreciated. I was looking at the HP Omni 100z Series http://www.shopping.hp.com/webapp/shopping/computer_can_series.do?storeName=computer_store&category=desktops&a1=Category&v1=All-in-One+PCs&series_name=100z_series&jumpid=in_R329_prodexp/hhoslp/psg/desktops/All-in-One_PCs/100z_series). What do you think?