Vista - %SystemRoot% being changed in script

Modified a script I found online that removes specified strings from the Path
environment variable. It works, but one thing it does that I don't get is
change "%SystemRoot%" to the hard-coded value of the variable
("C:\Windows\system32", for example).

Can anyone tell me why it does that, or how I can prevent it?

Here's the code:

Option Explicit
On Error Resume Next

Dim objReg, strComputer, strValueRight, strValueLeft
Dim strSearchFor, strKeyPath, strEntryName, strValue
Dim strTotalLength, strSearchForLength, strStartAt
dim strArraySearchFor

Const HKEY_LOCAL_MACHINE = &H80000002
strComputer = "."
strArraySearchFor=Array("C:\blah;")

' Connect to the registry (StdRegProv)
' Get the value for strValue (GetExpandedStringValue)
Set objReg=GetObject _
("winmgmts:{impersonationLevel=impersonate,(Security)}!\\" & strComputer &
"\root\default:StdRegProv")

strKeyPath = "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
strEntryName = "path"
objReg.GetExpandedStringValue
HKEY_LOCAL_MACHINE,strKeyPath,strEntryName,strValue

If (Right(strValue, 1) <> ";") Then
strValue=strValue+";"
objReg.SetStringValue HKEY_LOCAL_MACHINE, strKeyPath,strEntryName, strValue
End if

For Each strSearchFor In strArraySearchFor
surgery
Next

Wscript.Quit(1)

Function surgery
' Calculates strStartAt which cuts the strSearchFor value from the path
strSearchForLength=Len(strSearchFor)
strStartAt = inStr(lCase(strValue), lCase(strSearchFor))

' Build the new path
' join the values to the left and right of strSearchFor
strTotalLength=Len(strValue)
strValueLeft=Left(strValue,(strStartAt-1))
strValueRight=Right(strValue,
(strtotalLength-strSearchForLength-(strStartAt-1)))
strValue=strValueLeft + strValueRight
' Reset the path in the registry (SetStringValue)
objReg.SetStringValue HKEY_LOCAL_MACHINE, strKeyPath,strEntryName, strValue
End Function

"Tony Logan" <TonyLogan@xxxxxx> wrote in message
news:765B1BC4-0C27-41BE-B90A-6EA278601912@xxxxxxThis is by design: When you read a registry key of the type Reg_Expand_SZ
then all environmental variables are resolved. You will have to "unresolve"
them by obtaining the value x=%SystemRoot%, then performing this function:
path = replace(path, x, "%SystemRoot%", 1, -1, 1)
(untested)

"Tony Logan" <TonyLogan@xxxxxx> wrote in message
news:765B1BC4-0C27-41BE-B90A-6EA278601912@xxxxxxBy the way - having the statement "On error resume next" at the top of your
program is not nice. It makes trouble-shooting very difficult. Much better
to insert specific code that deals with errors, e.g. by checking for the
existence of a file *before* attempting to open it. Alternatively you could
cover individual blocks of code with an "On Error" statement and take
appropriate action when an error occurs (which you can determine by checking
err.number).