how to deny "goto next page"?

Hi to everyone, I read the help on line and NSIS site but I didn't find a solution for this problem. Someone have a suggestion for don't allow that install process could start?

My target is to update a file and user should choose right folder.

I tried with this script, but the result is that the installer will be closed if doesn't find right file. What I would is that the installer doesn't "Goto next page" untill user choose right folder. (at the startup installer reads Install path in the registry)

Function .onVerifyInstDir
IfFileExists "$INSTDIR\MyApp.exe" +3 0
MessageBox MB_OK "MyApp doesn't exist. Please select MyApp directory."
Abort
MoreInfo::GetProductVersion "$INSTDIR\MyApp.exe" ;get exe version (MoreInfo plug-in)
Pop $1
StrCmp $1 "3.1 " +3 0
MessageBox MB_OK "Invalid version!$\rPlease select MyApp directory."
Abort
FunctionEnd

What is causing the installer to close? Is it the Abort calls?

Stu

This works fine for me (attached). Don't put any message boxes in there because it will spam the user multiple times.

Stu

Hi Stu, thanksss for your help now I've found My mistake.

MY MISTAKE was in the "jump to line n.r X o Y" in the event "onInit" and I've leaved wrong and true strings:

Function .onInit
Processes::FindProcess "MyApp.exe"
StrCmp "$R0" "0" +3 0
Messagebox MB_OK "MyApp doesn't exist. Please select MyApp directory."
Abort
ReadRegStr $1 HKCR "MyApp\Path" ""
; IfFileExists "$1\MyApp.exe" 0 +3 ;!!!THIS STRING IS WRONG BEACAUSE NEXT IfFileExists SHOULD NOT BE PRESENTS TWO TIMES!!!!!!!!!!!
IfFileExists "$1\MyApp.exe" 0 +2 ;!!!THIS IS TRUE
StrCpy $INSTDIR "$1"
FunctionEnd

Ciao
Bruno

PS: in the orginal script I dint' wrote two IfFileExists commands so "+3" was wrong because goes directly to next event witout reading "FunctionEnd"

orecchionebruno: I suggest you start using LogicLib to simplify your code. Instead of IfFileExists etcetc, you can do
${If} ${FileExists}
stuff here
${Else}
other stuff here
${EndIf}

And so on and so forth.

Ok I'll do it, thankss