You should never assume a hard coded drive, whenever possible use a variable or read from the Registry. Remember, NT/2000/XP may not be installed on the C: drive, so hard coded entries to C: would fail. By default this location has EVERYONE FULL NTFS rights.

Here is another method of determing location.

code:
$DataLocation = READVALUE("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders", "Common AppData")
$NavGRC = "$DataLocation\Symantec\Norton AntiVirus Corporate Edition\7.5\"