I've been using RC1 on Win98 SE. When I uninstall RC1 things don't seem to go right. I don't get the usual status bars showing the uninstall process.
When I install RC3 only the browser works, and it doesn't work completely. Some site buttons and "right click" do not work. And mail is totally unavailable. I have gone thru this process repeatedly with about the same result each time. Sometimes after installing RC3 I can open mail, but not the mail and browser at the same time. If I reinstall RC1 I'm back to normal.
