Brokers often have it. Look on trusted broker sites.
If you had used this (before posting,) you would have found (among 100+) Where to download MT4? - General - MQL5 programming forum 2017.04.31
It has been years since you could download MT4 from Metaquotes. You can only get it from a broker's website.
Where
to download the orginal MT4 installer - MQL4 programming forum
2018.01.29
Possibly the "clean MT4" download link:
MT4 download
- General - MQL5 programming forum #2
Possibly MetaQuotes' MT4 Installation Link

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MT4 has stopped working completely. That annoying "Common error" again. And again. And again.
I tried all tricks I know to recover from it but none is working. I decided to reinstall.
I went here: https://www.metatrader4.com/en/download
First, it won't give me the full payload .exe. It gives me an installer that pulls mystery content from the Internet and installs whatever it wants behind my back.
Then when it's done, I see it has installed MT5!
Why do they do that?! Look at the page for yourselves, it clearly says "Download MetaTrader 4 for PC and create a demo account."
Why do they promise MT4 and install MT5? What is the point of being surreptitious like that?
Finally, WHERE can I get MT4? 4, not 5.
TIA.