if you get Assassins Creed 2, you better pray your connection to the internet doesn't go down or else you won't be able to play it at all and you will lose everything you have done. AC2 has a very anal policy that states if you are not online and connected to our server you don't play and you lose everything.
There are classic games on Steam and Direct2Drive you can get that will run on your machine. Personally, I am look forward to Metro 2033.
I know this is sort of off topic here, but what did u mean by "lose everything"?