I agree with ky;

 MSE was the last AV I used on my XP system, and it never gave me any grief. I considered its protection equivalent to the Windows Defender AV for Win 10. MS AV products had a bad period of independent test results a few years back, but test have recovered and compete with the best paid AV products available.

Like Win 7 itself, I suspect MS support for MSE will end in January of 2020.

Dale, Have you checked in the settings, to see if you can disable that notice?... I'll try to check later today (when I'm on a Panda system) to see if I can find something, as I don't seem to be getting a "nag". If you're using Windows 10 (or Win 8, 8.1), and you disable [or uninstall] Panda, then Windows Defender should automatically activate itself as the default anti-virus protection.

This machine has Windows 7, did not see any option in Settings, but did turn off Panda News.

If you're on Win7, then Windows Defender is NOT what you want... rather, (if you want to use a Microsoft anti-virus) you'll need to download, install, and enable Microsoft Secuity Essentials https://www.microsoft.com/en-us/download/details.aspx?id=5201

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Windows Defender, on Win7, is "merely" an anti-spyware program. 

Windows Defender, on Win8/10, is an anti-virus program.

Great source for confusion here.

 

So if I go with MSE, will I need Panda? Is Panda simply an anti-virus, or does it do more?

While there's a "blur"/overlap nowadays between anti-virus, anti-spyware, &etc., your choice on Win7 should be EITHER MSE or Panda, but not both.

Either should be sufficient for your safety.   But if you wanted something additional for extra coverage, I'd go with MalwareBytes3 PREMIUM (if you have, or are willing to get, a license for the paid version).   Some people say MalwareBytes is sufficient protection by itself (i.e., without a separate anti-virus program), while others advocate its use in addition to an anti-virus.   I take the latter approach.