I tried normal quit, and it closes and immediately re-opens.
I tried force quit, and it closes and immediately re-opens.
I tried force quit from the Activity Monitor, and it closes and immediately re-opens.
I tried to restart; this was not allowed because Chrome was open.
I turned off using the power button, and turned back on. Chrome opened (despite not being in my login list, and despite me specifying NOT to open the windows that were previously open)
I tried to delete Chrome; not allowed because it's open.
I tried to force quit then immediately delete, but it opens so fast I can't do that.
I used the terminal rm -rf method of deleting, and pages of text appeared, all saying essentially this but with different things between 'contents' and 'permission denied'. rm: /Applications/Google Chrome.app/Contents/_CodeSignature/CodeResources: Permission denied
Does anyone have a clue what's going on? I am out of ideas.
You might try doing part of what Byron suggested, but rather than a shutdown, force a restart. In Terminal, sudo restart -h now followed with your password will force a reboot. When you hear the startup chime, press and hold Command-S to enter single-user mode. Then use rm -rf on the Chrome app, and also delete the ~/Library/ApplicationSavedSate/com.Google.Chrome.savedState directory. Reboot again.