Actually, after doublechecking that.. if you want to install if the key doesn't exist, it should probably be:

code:
IF KeyExist("HKEY_CLASSES_ROOT\Avg.kernel")
? "Avg installed....
ELSE
"SHELL @SCRIPTDIR + "\avg.exe /s"
ENDIF
I'm just guessing, but this checks to see if the key is there, and if it's not it runs the avg.exe silently from the kixtart folder.

Brian