I tried your code and it ran fine here (after substituting my own music file, of course). What exactly is not working in your program?
Could it be that your music file is too large and it's just taking a long time to load it on your machine? Did you try to see if it works with any other music files?
By the way, here's your code in actual code tags (with proper indentation

)
load music "media\mario theme.mp3", 1
set text font "Jokerman"
ink rgb(255,255,21),0
set text size 24
Print "Welcome to Free Slots where you win nor lose any money"
Repeat
Repeat
Play music 1
x=1
Input "Press one and enter to begin", Key
If x=key
right=1
Else
right=0
Print "Please press 1 and enter"
Endif
Until right=1
Randomize (Timer())
N1=RND (7)
Randomize (Timer())
N2=RND (6)
Randomize (Timer())
N3=RND (8)
Print "Below are your numbers"
Print N3, N2, N1
If N3=N2 and N2=N1
Win=2
Print "Jackpot!"
Endif
If N3=N2
Win=1
Print "Well done"
Endif
If N3=N1
Win=1
Print "Well done"
Endif
If N2=N1
Win=1
Print "Well done"
Endif
If Win=1 or Win=2
Print "Winner!"
Else
Print "FAIL"
Endif
Until Win=1 or Win=2
Print "the game is over"
y=1
Repeat
Input "press 1 and enter to quit", Key2
If Key2=y
quit=1
Else
quit=0
Print "Please press 1 and enter"
endif
Until quit=1
Print "Press any key to exit"
Wait Key