Security software on new install of win 7 64Pro

Hello, I'm posting here because I don't know where I should be posting! I'm not used to forums at all.
I've just done a clean reinstall of win7 64 Pro on an old dell e6420 that got a windows 10 update by mistake a long time ago a time ago and never worked properly after that. Well now it's up and running just fine with windows 7again, but I can't put MSE on it.
My question is - what can or should I use instead? MSE (with nothing else) has been working fine on my old HP desktop win 7 for ages, but it seems that's no longer an option for the dell. Suggestions please?
Thanks, PosslPussl

As SIW2 suggested, disable Win updates and use Single file with all updates - Simplix

PosslPussl said:

it's up and running just fine with windows 7again, but I can't put MSE on it.

You can still download MSE from Microsoft here, and it should still install.

https://www.microsoft.com/download/details.aspx?id=5201

If it won't install then, as SIW2 says, your W7 may be missing some required updates.

MSE will be supported for engine and definition updates until January 2023.

Well I don't know where I got the idea the MSE wasn't available for download any more, but I obviously got it wrong. (I do lots of dumb things these days, I'm past my use-by date you know)
I downloaded the Simplix update package, and MSE from the microsoft site, it all went smoothly and now the MSE icon is cheerfully glowing green at me from the system tray. So thanks a lot SIW2 and Megahertz07 and Bree, your help is much appreciated. Problem solved.

PosslPussl said:

Well I don't know where I got the idea the MSE wasn't available for download any more....

Probably from Microsoft. Their left hand and right hand apparently aren't on speaking terms....

Microsoft said:

Microsoft Security Essentials reached end of service on January 14, 2020 and is no longer available as a download....

What is Microsoft Security Essentials?