You could do
import random
print """\t\t\tWelcome to \"Guess the Number\"!
\nThink of a number between 1 and 100.
try to guess it in as few attempts as possible.\n"""
number = input ("Enter the number: ")
guess = random.randrange (100) + 1
tries = 1
useds = []
while (guess != number):
if (guess > number):
print "You chose", guess, "the number is Lower ..."
useds.append(guess)
else:
print "You chose", guess, "the number is Higher ..."
useds.append(guess)
guess = random.randrange (100) + 1
if guess in useds:
while guess in useds:
guess = random.randrange(100) + 1
else:
tries += 1
print "You guessed it! The number was", number
print "And it only took you", tries, "tries!\n"
raw_input ("Press <ENTER> to exit.")