The Sims 2 Pets Freezing?

Okay I just got my entire laptop wiped after my antivirus.com”target=”_blank”rel=”external”title=”fave anti-virus” >anti-virus software broke down and let in a load of viruses and spyware, so I had to reinstall all my programmes. I was reinstalling my old versions of the sims 2, open for buisness, nightlife, and pets. I bought these games years ago, and they have so far worked on every computer i have had until now. All the computers before were windows XPs and were desktop computers, but now I have a dell laptop with windows 7 home premium. Anyway, I go onto the game and it runs fine for a while, but if i spend a while in one lot then it crashes on me. I can make it last longer if I save the game a lot, but i keep forgetting, and end up loosing all my stuff. Running it in XP compatibility (service pack 2) mode makes no difference. When I say it freezes, I mean it just stops and makes horrible noises, and nothing I do will do anything. I just have to hold down the power button until it goes off. I was also going to put the university expansion pack on, but i didn’t because I discovered this problem. I don’t think contacting the place i got the games from, or contacting the makers will do anything, because my games are so old.
My laptop is a dell inspiron 1545, with windows 7 home premium,2.10GHz pentium dual-core processor, a 64-bit Operating system, 3.00 GB memory and 199 GB free of 232 in (C:) drive.
If anyone can help I would be very grateful.