I've had just install an expansion pack (the Sims 3 Generation) and it said unknown error occured and i'd would like to uninstall that game on orign but when i used the uninstaller it said choose from this list which game would you like to uninstall but there is nothing there for me to choose from.
@KatieDaviot18 Do you have a mac? The unknown error issue is quite common in mac OS, and usually fixable. It might not be necessary to uninstall Generateions entirely. Instead, you could first try steps four and five in Bluebellflora's excellent guide to installing TS3:
If those two steps don't fix the unknown error issue, you can do a manual uninstall—instructions are linked in the intro of the above post. Then follow the guide to reinstalling, making sure that your game runs after each step. If it doesn't, please post back here with your computer's specs, along with a list of the packs you've installed so far.