newbie ? about sims & its expansions

[tngoy]

I installed a cracked version of the sims and have been playing it for a while. This weekend, I got a copy of sims hot date and installed it. It appears that the hot date overwrites the sims. Currently I have to install the sims on one computer and hot date on another computer. Is there any way that I could install both games and play them on ONE computer? Any idea or suggestion is really appreciated. Thank you very much