QuickScript.ahk

; The letters the random string will be generated from
LETTERS := "aaaaaabbcccddddeeeeeeeffgghhhhhiiiiijklllmmmnnnnnoooooppqrrrrsssssttttttuuuvwwxyyz                "

; The length of the randomly generated string
MINIMUM_CHARACTERS := 50
MAXIMUM_CHARACTERS := 100

Random, RepeatCount, MINIMUM_CHARACTERS, MAXIMUM_CHARACTERS

MButton::
  result := ""
  Loop %RepeatCount% {
    Random, rand, 1, StrLen(LETTERS)
    result := result SubStr(LETTERS, rand, 1)
  }
  SendInput {Raw}%result%
return