I guess that means we aren't going to get to read the dxdiag report? Uhm, okay...
The heavier EPs, and again Pets is the heaviest of all of them, practically demand a dedicated graphics card of sufficient strength to function well. Among other things, the rendering of animal fur, even if you don't have any animals around that are particularly fluffy, is likely going to be too much for integrated graphics to handle. You might try turning all of your graphics settings in Game Options down to the absolute minimum and switch off Advanced Rendering to see how the game behaves (it will look awful most likely, but the point would be to see if it runs without crashing every few minutes) and then maybe if successful increase a setting or two a little at a time until the game looks fun enough to play again.
To relieve stress on the game, play in offline mode (meaning don't login at the Launcher or in-game levels), switch off the in-game TS3 Store shopping experience, the interactive hidden object startup game, and scrapbook memories.
And you might try pulling out your entire TS3 user game folder from Documents and set it aside for safekeeping. The game will spawn a new game folder for you with no added content or saves in it, but those will still be safe back in the pulled out folder. Then see how a new test game with no added content runs in a known to be gentle to play world like Sunset Valley, Twinbrook, or Riverview -- not Appaloosa but only because I would expect it to have or draw in too many animals from the very beginning.
Hope some of this helps, but there may not actually be any magical types of solutions on integrated graphics.
