Help with a batch file script to query whether a registry key value exists

Hi all,

I need some help with a batch file to query whether a registry key value exists.  

If it does exist I want the script to end, but if it does not exist I want the script to execute an exe installation.

I know I have done this in the past but cannot quite get it working.  I believe I need to use REG QUERY and then %errorlevel% but I cant quite get it right.

The reg key value I am trying to query is [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{26A24AE4-039D-4CA4-87B4-2F83217045FF}] DisplayVersion="7.0.450"
fieldjAsked:
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oBdACommented:
Try this; just add your installation code after the last line:
@echo off
setlocal
set Key=HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{26A24AE4-039D-4CA4-87B4-2F83217045FF}
set CheckVersion=7.0.450
set DisplayVersion=n/a
for /f "tokens=2*" %%a in ('reg query "%Key%" /v "DisplayVersion" 2^>NUL') do set DisplayVersion=%%b
echo Installed Version: %DisplayVersion%
if %CheckVersion%==%DisplayVersion% (
	echo Already installed.
	goto :eof
)
echo Installing new version %CheckVersion% ...

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fieldjAuthor Commented:
Thanks OBda, this is looking really good.

I just need to do a bit more testing but it looks very promising at the moment.
fieldjAuthor Commented:
Script works perfectly.  Thank you.
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