Some older games REQUIRE the flash file to be named precisely "flash.ocx" --- which is what was used many years ago. Nowadays, Flash uses a longer name, based on the file's version.
For your windows 7, 64 bit system, I believe the flash file you want should be located in the
C:\WINDOWS\systemWoW64\Macromed\Flash
subdirectory... see if you can find a file there named (something like) Flash32_11_3_300_257.ocx .
If so, RIGHT-click on that file, select COPY. Move your cursor to any blank space on your desktop, RIGHT-click and select PASTE. RIGHT-click on the desktop file you just created, and RENAME it to simply "flash.ocx" [CONFIRM the file-rename, if asked]. Finally, "drag" the renamed file from your desktop, into the Flash folder mentioned above [CONFIRM file-movement of Read-only file, if asked].
Emphasize you now will have two Flash-related .ocx files in that subdirectory --- the one with the original (long) name, as well as the copy you created with the shorter name. Hopefully, that will do the trick, and allow your game to work.
Note: If this solves your SIMS problem, you will have to repeat the process everytime you run the Flash UNinstaller, to update to a newer version.