Let's start with the Error16 if we could. How large is your hard drive and how much free space has it got? If you have multiple drives with Windows on one and the game installed on the other, then list both. Are you still in the habit of loading up or starting new games after playing an existing one without quitting the game entirely to the Desktop (or Origin) in between as reported a while ago, or is that all in the past? Is there any evidence of your computer malfunctioning in other ways, not related to the game?
Repair Game doesn't really do anything for TS3 unless Origin is acting up and not starting the game up properly. Unlike with TS4 and other games, it really just rearranges things so that Origin can launch it better.
Then perhaps we can move on to the aging issue.