Dell Vostro 1700 laptop (with separate numeric keypad next to regular keyboard)

I started having problems where hitting one key would return two characters...the intended key plus an adjacent key.

On the keypad, "7" would return "57" or "75"...but subsequent hits would return "7" . Similar problems were happening on the regular keyboard as well. So, "d" would return "dc" the first time, then "d". "L" would return "L.", etc.

because it was a "generalized" issue, I don't think it was due to dust or debris under any specific key.

It's not doing it now but it was vexing. Does anyone know what could put the machine into such a mode?