How do you uninstall the latest Patch?

[ilovethesims2loadsx]

I NEED to uninstall this patch and have tried everything I usually do when its messed up but that hasn't worked!
I need to know how to uninstall a patch MANUALLY without uninstalling any games especially the base game!
Does anybody have a single clue how to do this because I'm litterally pulling my hair out!
I click on the launcher and it comes up with the message:
"There was an error during startup. Please see the Log for more details."
I've tried uninstalling and reinstalling origin about five times, uninstalling games and reinstalling them and nothings worked!
Please hurry I'm going on holiday tommorow and I'd hate this annoying problem to be waiting for me when I get back on Friday, infact what I'd probably like the most is for me to be able to play this when I get back!
Please answer :!: :!: :!:

[whiterider]

You can't uninstall a patch without uninstalling and reinstalling all your EPs, and the basegame. You can't manually uninstall the patch because it changed all your game's files: the older versions don't exist any more, so you can't undo the changes.

However, you probably don't need to uninstall the patch. Have you tried Game Help:TS3 Bypassing the Launcher? If that works you can play at least: if so, then you can try fixing the launcher later using these instructions: Game Help:Launcher Issues.