Backspace not working properly inside vim comEmu

Vim seems to be confused about what your terminal sends as the erase character. As this varies between ^? (Ctrl+?, or DEL for "delete") and ^H (Ctrl+H or BS for "backspace"), Vim depends on someone telling it what to expect.

That shouldn't happen unless

• you're changing related settings in your vimrc,
• you're changing the value of the TERM environment variable,
• your terminal information database is messed up, or
• you're suffering from a gremlin infestation.

For troubleshooting, try to run the command stty erase ^? before starting Vim, and see if this fixes it. Enter the ^? not separately as ^ and ?, but by first pressing Ctrl+V, then your Backspace key. If your shell is well-behaved, this should produce a literal representation of whatever your terminal sends when you hit that key.

• The native terminal type for Putty (default config) is "xterm" not "vt100".
• You shouldn't need to hardcode TERM in .profile.
• Use stty intr ^C on server to specify what Ctrl+C does.
• Putty has a "Reset Terminal" option in its menu
• Putty's menu has a "Special Command" of "Are you there" (the answer is "[YES]").
• I don't see how those aliases could work, Putty doesn't send __A.

Modern vi uses terminfo to find an initialisation string to send to Putty. Your install of vim might be using termcap instead (see vim --version | grep terminfo: the result should include either -terminfo or +terminfo)