Hi,
I really need help, I have no idea what to do and I've really messed up.
So a few weeks ago, I was playing my Sims Games (3&4) totally fine. No problems or anything. Recently I had done Virus scans & deleted tons of my irrelevant personal files, then went to go back to playing and whenever I try to open it, I get this error saying
"TS3.exe - System Error
The code execution cannot proceed because MSVCR100.dlll was not found. Reinstalling the program may fix this problem"
So me being me, having no clue what I'm doing, proceeds to delete my Sims 3 Base game not knowing what I'm doing & emptying the recycling bin in hope of reinstalling my game. Stupid idea. Didn't do a thing. I tried recreating my game files. Same thing. So I tried repairing my game. Nothing again. By this time I was in tears, having a panic attack, I feel so stupid, because I honestly don't know what I've done.
I'm always causing issues with my computer. I know now it's a system error but I just don't know what to do. I've had so many issues with the Sims in the past, I literally cannot handle that game anymore. It's caused me years and years of issues and I'm honestly considering just waiting until I get a new computer before I retry playing it. I know I probably seem so dumb, but is there a safe place I can find the MSVCR100.dlll file for Windows 10 so I can play the Sims in (Hopefully) peace? Or have I accidentally deleted this file? Please, help!

My suggestion is to actually go in and uninstall the game and all expansion packs. If you still have your sims 3 folder, back up your downloads and mods. I myself wouldn't save anything else. If you deleted files unknowingly it's hard to say what all is missing. Deleting files isn't the same as uninstalling.

Once you do a full uninstall of the game, one by one reinstall. A full fresh install of the files that way we make sure all files are new and that we aren't missing any somewhere.

I don't believe in your case refreshing the game file will work. If a file in the core is missing that won't fix the issue.

Earlier this year I had a corruption somehow happen with my basegame install. This was the only way I could fix my game. Let me know how it goes

This link will also help with the missing file https://www.lifewire.com/how-to-fix...-errors-2623799. NEVER download that file. If you aren't familiar enough with going into safe mode or doing windows repairs please seek help or have someone else do it. I would help but not easy over messages.

I will offer some slight extensions of the above advice, excellent though it is. After doing or attempting an uninstall of all EP/SPs and then the base game again, and by this we mean proper uninstalls not only through Origin but also through the Windows Programs and Features control panel, you will want to also uninstall Origin itself from the same Control Panel.

Clean the Registry with the free version of Piriform's CCleaner.
https://www.piriform.com/ccleaner

You actually need to clean out remnants of the original base game install that would be left behind from merely deleting the program files (yikes, never do this!) but hopefully CCleaner can do it for you.

Reinstall Origin. Did your TS4 install stay intact throughout? If it works, try using Origin to install the TS3 base game (only) to see if that works too. You can worry about the EP/SPs later.

If at this point you still get the dll errors, look up in the Origin pull-down menus for an offer to try the beta version of Origin. Try that and, if still no dice, back to the pull-down menus to select the regular (non-beta) version again. We don't know why exactly, but sometimes the beta version or switching between the beta and regular versions of Origin helps resolve "missing" dll errors when the Windows component in question is not really damaged or missing.

And if still no dice after all that, I would say that a component of Windows that Origin and the games need to run, Visual C++ 2010 in particular (must be the 2010 version), is indeed missing or damaged. See the post from EA_Tom around 9 posts down on this page from the EA Answers HQ board for suggested resolution.
http://answers.ea.com/t5/Technical-.../4702068/page/2

MSVCR100.DLL is a Microsoft Visual C++ file and is required by applications which were made with Visual C++, you can fix it by downloading the installer from Microsoft and reinstall it, however if your antivirus told you to removed them manually and that's what appears to be as you mentioned them above, then it is possible or likely that your system is infected with malware from third party software included in the download that you may have downloaded somewhere from the internet. You can check this by going to "Programs and Features" by right clicking the "Start" button if you're on Win 10, then from "Programs and Features" you can check if there's any third party programs installed.

Reinstalling Microsoft Visual C++ (2010 and 2013 for TS3 and TS4) may fix the problem and you probably will be able to run your game again but that won't removed the malware if your system is already infected, and if this is the case you may need to find an antivirus that can detect and remove the malware without you having to delete them manually. Removing malware from infected system is tricky and time consuming because most of them doesn't work like a virus and well hidden somewhere in your system that's why it is very hard to find them. And if this is actually the case, the safest and easiest way to removed them from your hard drive is by booting your computer from clean Win 10 or any Windows OS installer, format every partitions and then follow with removing or deleting all partitions, then create new partition(s) and format them again and reinstall your Windows OS, these steps will remove any malware (even the ransom attack malware) but you'll likely lost all of your important data as well if you don't have backup.

The reason why I mentioned this, is because it is unlikely that any antivirus tells the user to delete MSVCR100.DLL manually, you may have deleted it by accident or it was told by your antivirus, and if this is the case then it's not normal and your antivirus is trying to tell you something suspicious that it can not fix them for you. Note: If this is all too technical for you, then you may need to get professional's help, because the problem is located in your system not from TS3 nor TS4.

Thank you all to the suggestions above, hopefully they'll all work & I will be giving them a go in the future & will let you know how they go, maybe via messages considering it may be a while since I'm quite busy right now.
The thing is, I thought maybe I had accidentally deleted it myself, since I have the normal Windows Antivirus that comes with your computer as well as Norton 360 and I highly doubt they would've deleted it. I checked my recycle bin and it isn't there, is there a way I can look for it on my computer? Because the file may well be corrupted, not deleted. Would I then download the Microsoft Visual C+++(2010 & 2013) and reinstall it if that was the case & replace the already existing file? I'm Windows 10, I don't know if I mentioned that.

Everything that has been removed from your recycle bin is gone, you won't find them anymore, go here to download any version you need from 2005 - 2017, make sure you download and install both x86 and x64 versions if your Win 10 is 64 bit version, don't worry about the corrupted ones, the installer will fix them automatically when you reinstall them, you need the 2010 and 2013 for TS3 and TS4 and the rest is optional, but you might need them all as well for other applications and programs.

I don't know much about Norton 360, I've tried many of different antivirus and malware but still not sure which one I would keep or to recommend, the Windows 10 Defender is pretty much detects and quarantines Malware threats, the thing you need to be aware of.. is when you download anything from the internet, you need to read and pay attention to what's included to avoid 3rd party software being included in the download, if you missed it.. there's still another chance to acknowledge by reading its terms of use and agreements if 3rd party software is also being included at the time you're going to install them, decline anything you don't intend to have or need to install, because if you accepted them all.. and it happened to be a malware, then it is then when the Windows 10 Defender will kicks in and protect the system, but if this happened.. it's kinda too late already if W10 Defender only able to quarantine them but can't removed them, the same thing goes with antivirus, so in order to protect from virus and malware threats, it's up to the user, you may need antivirus and malware if you allowed any usb storage device plugged in to your computer from another computer, so just make sure you know what goes in and what goes out from your computer. For prevention purpose I personally backup my fresh and clean W10 installation as an image and my personal files as well in my external hard drive, so if anything goes wrong.. I just wiped them all and restore them back fresh and clean from my backup.

Thank you so much! I will definitely keep a lot more attention to all this. I noticed I have all my Microsoft C++'s installed, so would I just redownload the ones I need for TS3/TS4? Will it just replace the old files or something? I am sorry if I am misunderstanding, I'm not good with all this computer stuff.

Yes, after you downloaded them, just run the instaler one by one, you'll need both x86 and x64 versions for Win 10 64bit, at the start of the installation it will give 3 options to re-install or repair and/or remove if I remember them correctly.

Alright! I'll give it a go. Thank you very much