@22950010288090 I'm sorry you can't get your save to load; I remember how upset I was when some of my own saves became unplayable. There is one more method you can try, but the chances of it working are pretty low. Start a new game in the same world as you were playing in before. Save it, quit, delete your cache files, and then go into the save's folder (inside Saves) and delete the file called [name of world].nhd. Copy the .nhd file from your corrupt save into this folder and then try loading the save. Like I said, this doesn't often work, but it's probably worth a shot.
The issue isn't that you're running a 32-bit game in a 64-bit OS; that's actually better than the alternative. But yes, the save corruption and crashing could both be due to the fact that TS3 is 32-bit, that is, it can only address 4 GB RAM at a time, although the limit is more like 3.7 GB. If it goes over, it can crash, or it data can be lost or corrupted. Or you may not be able to properly save, which takes more memory than regular gameplay. (Playing on a 32-bit system would be worse because the OS would take some of that 4 GB RAM for itself, leaving the game much less to work with.)
There are plenty of ways to lower TS3's RAM use. Play while your computer is offline, or at the very least don't login at either the launcher or Main Menu. Disable in-game shopping. Turn off memories and the hidden object loading screens. In graphics options, keep the water and high-detail lots settings low, since these are the most demanding options; I have these at "mirrors only" and 2, respectively. Larger worlds will be need more RAM to run, whether they have high populations or are just physically bigger. You can find other tips here:
https://www.nraas.net/community/TIPS-FOR-BETTER-GAME-PERFORMANCE
Another cause of high memory use is a poorly made world, like Isla Paradiso. Sims get stuck, and the game engine overexerts itself trying to free them. The solution is to avoid badly made worlds or play in fixed versions.
If you have a strong graphics card, you should also take steps to cap your frame rates. TS3's fps limiter doesn't work, and strong cards can damage themselves from overwork if the rates aren't capped. The tool(s) you use to limit fps will depend on the make of your card. If you're not sure what kind of rates you might be getting, you can open the cheats console (crtl-shift-c) and enter "fps on" without quotes, and a number will appear in the upper right corner. ("fps off" makes it go away.) Anything over the refresh rate of your monitor—likely 60 Hz—is too high.
In the future, you can use "save as" and rename your saves periodically, so you'll always have backups in case your game becomes corrupt. You can keep the last 4-6, or however many makes you comfortable, and delete the older ones when you're sure you don't need them anymore. You can also move backups out of your game folder and to an external drive if you prefer.
P.S. After losing a number of saves, I started using mods and have never lost one since, but I have no idea if that's something you'd like to try. If so, I can point you to the right place, even if mod help itself isn't something we really do here.