Delete a letter from a string

Run this program:

player_name$="Trev"
Replacement$=Right$(player_name$,1)
Replace(player_name$,replacement$,"Z")
Print player_name
Stop
WaitKey

it should say TreZ instead of Trev

player_name$="Trev"
Replacement$=Right$(player_name$,1)
player_name$ = Replace(player_name$,Replacement$,"Z")
Print player_name
Stop
WaitKey

THANKS!!

Dim players_characters(7)
Global player_name$
Global actual_character$
Global number_of_characters


Graphics 800,600,16,1
SetBuffer=BackBuffer()

While number_of_characters<7
Cls
FlushKeys()

While Not players_characters(number_of_characters)
Cls 
players_characters(number_of_characters)=GetKey()
Text 400,200,"Please enter your name:",True,True
Text 400,300,player_name+"$",True,True
Flip
Wend

actual_character$=0
actual_character$=convert_to_string(players_characters(number_of_characters))
If players_characters(number_of_characters)<>13 And players_characters(number_of_characters)<>8 
player_name$=player_name$+actual_character$
number_of_characters=number_of_characters+1
Else
If players_characters(number_of_characters)=13
Exit
EndIf
If players_characters(number_of_characters)=8
delete_letter()
EndIf
EndIf
Flip
Wend

Print "This program completed succesfully, Your name is:"+player_name
WaitKey()
End

Function delete_letter()
If number_of_characters>0
players_characters(number_of_characters)=0
actual_character=""
number_of_Characters=number_of_characters-1
players_characters(number_of_characters)=0
Replacement$=Right$(player_name$,1)
player_name$=Replace$(player_name$,replacement$,"")
Cls
Text 400,200,"Please enter your name:",True,True
Text 400,300,player_name,True,True
Flip
EndIf
End Function

Function Convert_to_string$(letter)
Select letter
Case 97
Return "a"
Case 98
Return "b"
Case 99
Return "c"
Case 100
Return "d"
Case 101
Return "e"
Case 102
Return "f"
Case 103
Return "g"
Case 104
Return "h"
Case 105
Return "i"
Case 106
Return "j"
Case 107
Return "k"
Case 108
Return "l"
Case 109
Return "m"
Case 110
Return "n"
Case 111
Return "o"
Case 112
Return "p"
Case 113
Return "q"
Case 114
Return "r"
Case 115
Return "s"
Case 116
Return "t"
Case 117
Return "u"
Case 118
Return "v"
Case 119
Return "w"
Case 120
Return "x"
Case 121
Return "y"
Case 122
Return "z"
Case 65
Return "A"
Case 66
Return "B"
Case 67
Return "C"
Case 68
Return "D"
Case 69
Return "E"
Case 70
Return "F"
Case 71
Return "G"
Case 72
Return "H"
Case 73
Return "I"
Case 74
Return "J"
Case 75
Return "K"
Case 76
Return "L"
Case 77
Return "M"
Case 78
Return "N"
Case 79
Return "O"
Case 80
Return "P"
Case 81
Return "Q"
Case 82
Return "R"
Case 83
Return "S"
Case 84
Return "T"
Case 85
Return "U"
Case 86
Return "V"
Case 87
Return "W"
Case 88
Return "X"
Case 89
Return "Y"
Case 90
Return "Z"
End Select
End Function

my player name input functions work ok,
but if you press backspace when there is nothing to delete the screen goes blank and I cant work out why

EDIT-
got it working but the REPLACE command removes all instances of a letter from a string if they are next to each other, dont know how to stop this

Function Backspace$(St$)

  If Len(St$) = 0 Then Return ""

  Return Left$(St$, Len(St$) - 1)

End Function

Also check out the Chr$(letter) and Asc(letter$) commands, so you can replace that very long function "Convert_to_string$".

Chr$() accepts a ASCII value and converts it to a character (like your function), while Asc() accepts a character and converts it back to a ASCII value.

thanks Rott and PowerPC,
once Im finished would it make a good entry to the code archives?
I cant find anything similar in there,

the reason I am doing this is because it makes it possible to use cool bitmap fonts instead of the 'unprofessional' INPUT command,

Sure, why not? Any contributions would always be useful to someone. Well, that's my opinion anyway!