I found it before on another computer, but now, i just cant find it

Program Files\Electronic Arts\The Sims 3\Game\Bin\Gameplay or C:\Program Files (x86)\Electronic Arts\The Sims 3\Game\Bin\Gameplay on 64 bit operating systems assuming you installed to the default location.

I did, but I cant find program files to begin with

If you go to your C:\ drive (assuming you just have one hard drive), you should see it listed. If you have 64 bit Windows, you'll see two - Program Files, and Program Files (x86).

I just cant find the C:\ i have looked everywhere. Sorry, if this seems stupid, but I have been on a mac up until now and am just lost

Lol!!! C:\ is the name of your main hard disk in your PC. So "C:\Program Files (x86)\Electronic Arts\The Sims 3\Game\Bin\Gameplay" means you start at the top, outside all your folders, and then find a folder called Program Files (or "Program Files (x86)") then inside that one called "Electronic Arts" and so on. You will need to use a utility that is always part of Windows, called Windows Explorer, which lets you move around in the folders and find files.

Depending on your operating system you can usually click on your start menu (the little windows icon on the bottom left of your screen) and click on Computer and it shows you your hard disk drives C: is usually the first on the list. Double click on that and you should see your program files folder. If it's not there it is possible hide a folder accidentally in which case click on organize - folder and search options - view and select show hidden, files, folders and drives. From there you can right click on your program files folder and select properties and unhide it.

Found it finally