@EspressoBean21 In the new account, have you specifically tried the Task Manager method? Please keep in mind that in an EA App install, the game will use TS3.exe and Sims3Launcher.exe, both without the W.
If this isn't helping, please look for any new errors in the Reliability Monitor. Hit Windows key-R and enter "perfmon /rel" without quotes, and you'll see a chart of errors and updates with a column for each day. Look for any errors that mention Sims 3 or the EA App from after you created the new account, or any errors that happened at exactly the time you tried to launch the game, again in that new account. If you find one, right-click on it and select "View technical details," then copy the info and paste it into a reply here.
Keep in mind that the Reliability Monitor only updates once an hour or so, meaning if you check it first and then launch the game, any new error might not be listed immediately.
If you don't see any errors, that's useful information too. But this sounds like the same processor-related error we've been talking about.