Hi! I'm Eric, a computer expert who's been paired with you through JustAnswer.com. I'm reviewing your question now, and will return w/ an answer soon!
Hi Fred! I haven't forgotten about you, but I *have* been under the weather today and not online. My sincere apologies to have kept you hanging. I'm going to eat some dinner here before "punching in," but I saw your message come through and at least wanted to quickly touch base.
It's about 7:30 EST now and I plan to be online for several hours come about 9PM EST. Are you free then, or is that too late? If the latter, can we schedule a time for tomorrow?
Thanks for your understanding.
Regarding the App Store issue, the most common issue is that the computer's data and time are incorrect (you'd think Microsoft could handle such a thing more gracefully, but...alas...):
If that's not it, we can "re-register" the Windows Store app:
powershell -ExecutionPolicy Unrestricted Add-AppxPackage -DisableDevelopmentMode -Register $Env:SystemRoot\WinStore\AppxManifest.xml
One of those two methods should fix the problem.
The issue with the Windows troubleshooters not downloading usually has to do with a malfunctioning firewall, but there are other possible causes. Try temporarily disabling your security software, and see then if you can get to the troubleshooters. If not, please let me know the text of the error you're seeing.