Somehow, I clicked something and my channel buttons all moved to the bottom and are covering Windows task bar. When I move the buttons to the top, mIRC still covers Windows task bar. How can I fix this?

I assume you have your Windows Taskbar set to Auto-hide. I would say you accidentally set mIRC to Always On Top.

Right-click mIRC's title bar, and uncheck "On Top."

Sorry to say I can't even find setting for Windows Task Bar and mIRC not set for always on top.

See if a reboot helps then. It might be a one time glitch in Windows.

No help with three reboots.

Right-click a blank area on your Windows Taskbar. Select Properties. Un-check "[x] Auto-hide the taskbar."

Thanks for your continuing help. The "auto-hide" in Windows Task Bar wasn't checked. I checked it and unchecked it. No help.

I'm out of ideas for the behavior as you've described it. Would you mind showing us?

Press the PrntScn button your keyboard to take a screen capture.

Open https://imgur.com/ and click on Upload at the top.

Press CTRL+V to paste your screen capture and click Start Upload.

Share the Imgur link with us.

Uploaded as mircsettings.jpg -- as you can see, there should be four lines of channel buttons.

I think you are talking about the switchbar, right click in an empty area of that bar with the 'channel buttons' and select position > top, if you want it on top.
But even at the bottom it shouldn't overlap the taskbar, that could be explained by the fact that you have mIRC running in fullscreen, you can press F11 to toggle the fullscreen mode

The channel names at the bottom of the mIRC screen. Should be four rows. That part would be okay if those were raised a bit. Also the minimize/maximize and X to close aren't showing.

You are a bit unclear, can you make a screenshot of what you mean? You can type /menubar on in any editbox to display the menubar, without it you cannot get the minimize/maximize/close buttons of a window when maximized

Where is the upload? You didn't follow my Imgur instructions.

It sounds like you might have the "Full Screen" option enabled?

BINGO! That fixed it. Many thanks, Khaled. You're the tops as always

Well, I suggested that in my first post

You are correct, Wims, and my apologies. I was looking at a different full screen setting and didn't find that one in Settings. I found it in View and things all okay now. Thanks for your patience and help.