When you use Windows XP's Remote Desktop Connection client, the computers that you connected to are remembered in an MRUn Value Name at HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client\Default.

When you connect to a computer, the new connection is named MRU0 and other value names are moved down sequentially.

I have scripted RDCForget.bat to remove one or more entries from the MRUn list, so they do NOT appear in the Computer box.

The syntax for using RDCForget.bat is:

RDCForget V|A|Computer1 \[Computer2 ... ComputerN\]

Where:

V          indicates that you want to view the list of saved computers.

A          indicates that you want to delete the entire list of saved computers.

ComputerX  indicates that you want to delete this specific computer name, or IP address, or leading portion thereof:
           192.168.0. would delete all computer whose IP address starts with 192.168.0..
           JSI would delete all computer whose name starts with JSI.

RDCForget.bat contains:

@echo off
setlocal
if \{%1\}
\{\} goto syntax
set action=%1
set action=%action:"=%
if /i "%action%" EQU "V" set action=V&goto OK
if /i "%action%" EQU "A" set action=A
goto OK
:syntax
@echo Syntax: RDCForget V^|A^|Computer1 \[Computer2 ... ComputerN\]
endlocal
goto :EOF
:OK
set key="HKCU\Software\Microsoft\Terminal Server Client\Default"
set fnd1=FIND "MRU"
set fnd2=FIND "REG_SZ"
:OK1
for /f "Tokens=1,2*" %%a in ('reg query %key%^|%fnd1%^|%fnd2%') do (
 set MRUx=%%a
 set MRUd=%%c
 call :doit
)
shift
if \{%1\}
\{\} endlocal&goto :EOF
set action=%1
set action=%action:"=%
if /i "%action%" EQU "A" goto syntax
goto OK1
:doit
if "%action%" EQU "V" call :regv&goto :EOF
if "%action%" EQU "A" call :regdel %MRUx%&goto :EOF
for /f "Tokens=*" %%x in ('@echo %MRUd%^|Findstr /I /B /L /C:"%action%"') do (
 call :regdel %MRUx%
)
goto :EOF
:regdel
set wrk1=%MRUx%    #
set wrk2=%wrk1:~0,8%
@echo Delete %wrk2% %MRUd%
reg delete %key% /V %1 /F
@echo.
goto :EOF
:regv
set wrk1=%MRUx%    #
set wrk2=%wrk1:~0,8%
@echo %wrk2% %MRUd%