Emacs does not recognize the alt modifier key

[Tim Johnson <tim@johnsons-web.com>]

Using emacs 22.3.1 on Slackware 13.0 32-bit, stock install.
FYI: Used emacs extensively at one time, after several years,
have resumed usage.

Emacs does not recognize the alt key on this Operating system. Emacs
does recognize the following modifiers: control, hyper and super. The
last two are set via xmodmap.  xev will recognize the 'alt' key as do
other applications - such as vim.

<esc> + char sequences appear to be interpreted the same as an alt-char
combination. (As I would expect)

Example: c-h,k <esc>-p => M-p (translated from <escape> p) runs the
command scroll-other-window-down.
But c-h,k <alt>-p => H-p runs the command backward-sexp
;; Note 'H-p' instead of 'M-p'.

I have not changed any of my emacs settings (that I know of) since I
used emacs on previous OSs (slack 10.0 and kubuntu).

Please advise.
thanks

-- 
Tim 
tim@johnsons-web.com
http://www.akwebsoft.com