My sims3 won't run in windows xp, it worked before but not anymore?

i had the sims 3, ambitions, and late night installed in my xp. played it for 5 months. and one day when i clicked the play button from launcher it didnt run. i didnt do anything with my computer before, it just stopped working like that. i checked the free space and there were still 5 GB free space. I tried to run the other application and they're all working well. anyone could help?