Hi Sonshine,
Before suggesting to get a new video card, Have you tried any of the tips in this thread?
Topic: Sims 3 - Tips for Crashing, Lag and Other Misc Tips
http://www.carls-sims-4-guide.com/forum/index.php/topic,20732.0.htmlHow long has it been since you've done a complete uninstall/reinstall of the whole game? If it's been awhile - longer than say 6 months to a year, give that a try.
After you've uninstalled the whole game, run a registry cleaner program. (Something like Ccleaner, It's free -
http://www.piriform.com/ccleaner/download)
This helps clean up temporary files, internet cache files and other files that are left behind that are no longer being used.
Then play the game awhile to see if that helps. If you find that it still crashes, then holler back and we'll see if we can find you an acceptable video card.
Hope this helps,
MrsFlynn
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Edited to add:
Factory Reset
[This is different from a total-game reinstall - This just sets the game back to factory default.]
Move your Sims 3 folder to the desktop or some where safe, and rename it something like Sims 3 Current. Click the Sims 3 icon to create a new Sims 3 folder.
Go To: ----> My Documents > Electronic Arts > The Sims 3
If you want to continue to play your previous game-saves, go into the Sims3 folder that you backed up and copy over your game saves, files and such over to the new game to see if that helps.
Saving folders/files to use on a different computer or to use as backup
http://www.carls-sims-3-guide.com/forum/index.php/topic,16414.msg313134.html#msg313134How To: Save Sims 3 Files From the Library (Exporting Files)
http://www.carls-sims-4-guide.com/forum/index.php/topic,20751.0.html