Python Quiz Game

import sys, os, random, csv

def welcome():
    print ("#####################################")
    print ("#  .::Welcome to The Music Quiz::.  #")
    print ("#           .:Version 1:.           #")
    print ("#####################################")
    print ("")
    Choice = input('Do you want to login or register? ')
    Choice = Choice.lower()

    if Choice ==  'login':
        login()
    elif Choice == 'register':
        register()
    else:
        print ('Enter login or register')

def register():
    print ('Follow the register instructions')

    username_check = False

    while username_check == False:

        username = input('Please enter a Username: ')

        with open('users.csv') as csvfile:
            reader = csv.reader(csvfile)
            for row in reader:
                if username == row[0]:
                    print ('Username not available, try again.')
                    username_check = False
                else:
                    username_check = True

    if username_check == True:

        password_check = False

        while password_check == False:
            password = input('Please enter a Password: ')

            score = "0"

            account = username + ',' + password + ',' + score + '\n'

            with open('users.csv', "a") as f:
                for row in account:
                    f.write(row)

            print ("Thank You for Registering, You can now login")
            print ("")
            login()

def login():
    logged_in = False

    while logged_in == False:
        username = input('Please enter your Username ')
        password = input('Please enter your Password ')

        database = open('users.csv')
        users = csv.reader(database)

        for row in users:
            if username == row[0] and password == row[1]:
                logged_in = True
                print ('Logged in successfully as ' + username)
                print ("")

                database = open('users.csv')
                users = csv.reader(database)

                for row in users:
                    if username == row[0]:
                        currentScore = row[2]
                        currentScore = int((currentScore))

                song_list = ''
                song_name = ''
                artist_name = ''
                song_letters = ''
                chances = 2
                score = 0
                quiz = True

                with open('songs.csv', 'rt') as f:
                    reader = csv.reader(f)
                    song_list = list(reader)

                print ("Your Highest Score is " + str(currentScore))
                print ("Can you beat it?")
                print ("")

                while quiz == True:
                    if chances == 2:
                        Song = (random.choice(song_list))
                        Song = str(Song)
                        Song.split(",")
                        artist_name,song_name = Song.split(",")

                    for char in "']":
                        song_name = song_name.replace(char,'')

                    for char in "['":
                        artist_name = artist_name.replace(char,'')

                    song_name.lower()

                    print ("You Have " + str(chances), "chances remaining!")
                    print ("The Artist of the song is " + artist_name )

                    words = song_name.split()
                    song_letters = [word[0] for word in words]

                    print ("The first letter of each word in the song name are " + str(song_letters))
                    guess = input ("What is the name of the song? ")
                    guess = guess.lower()

                    if guess == song_name:
                        print ("Correct the Song was " + song_name, "by " + artist_name)
                        score = score + 3
                        print ("")
                        print ("You scored 3 points for guessing the song the first try")

                    else:
                        print ("That is incorrect, Try again")
                        print ("You have 1 chance left!")
                        chances = chances - 1

                        guess = input ("What is the name of the song? ")
                        guess = guess.lower()

                        if guess == song_name:
                            print ("Correct the Song was " + song_name, "by " + artist_name)
                            score = score + 1
                            print ("")
                            print ("You scored 1 point for guessing the song the second try")
                            chances = 0
                            chances = 2

                        else:
                            print ("")
                            print ("You have run out of lives!")
                            print ("You Scored " + str(score), " points")

                            if int(score) > int(currentScore):
                                currentscore = score

                            quiz = False

            else:
                logged_in = False
                print ('One or more details are incorrect, Try Again')

welcome()