Vista - diskspace on Exchange Servers

I have a script here to check diskspace but its all over the place
unfortunately.

I am trying to only query the E, G and I drives of a list of servers.
Some of these servers have only E and G drives whilst others have E, G
and I drives. Basically these are exchange log areas and we are
trying to keep an eye out on the diskspace so it does not run out on a
daily report.

If any one can help I would appreciate it please. The script is below
which at the moment list percents and all drive letters at the
begining but I need to maybe put a case statement in to only check for
the needed drive letters and how to read the list of servers in
through a text file outputting drive letter such as

E: freespace nnnn percent free

Thanks.

Simon

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Const HARD_DISK = 3

strComputer = "."
Set objWMIService = GetObject("winmgmts:" _
& "{impersonationLevel=impersonate}!\\" & strComputer & "\root
\cimv2")

Set colDisks = objWMIService.ExecQuery _
("Select * from Win32_LogicalDisk Where DriveType = " & HARD_DISK
& "")


For Each objDisk in colDisks
'to get GB size, divide by 1073741824 (same as
dividing space by
' 1024 / 1024 / 1024)
strDiskDrive = objDisk.DeviceID
strDiskUsed = FormatNumber((objDisk.Size -
objDisk.FreeSpace) / 1073741824)
strDiskSize = FormatNumber(objDisk.Size /
1073741824,2)
strDiskFree = FormatNumber(objDisk.Freespace /
1073741824,2)
strPercFree = FormatNumber(objDisk.FreeSpace/
objDisk.Size,2)
strPercFree = strPercFree * 100 'multiply percent by
100 to get whole number
wscript.echo strComputer & vbtab & " " & strDiskDrive
& " " & strPercFree & "% free."
Next


For Each objDisk in colDisks
Wscript.Echo "DeviceID: "& vbTab & objDisk.DeviceID
Wscript.Echo "Free Disk Space: "& vbTab & objDisk.FreeSpace/
1048576
Next


wscript.echo "+++++++++++++++++++++++++++++++++++++++++++++++++++++++"

For Each objDisk in colDisks

If objDisk.DeviceID = "E:" Then
'wscript.Echo objDisk.DeviceID & vbtab & objDisk.FreeSpace/1048576
mynum=objDisk.Freespace
Myroundnum=Int(mynum/1048576)+1
wscript.Echo objDisk.DeviceID & vbtab & Myroundnum
End if

If objDisk.DeviceID = "G:" Then
mynum=objDisk.Freespace
Myroundnum=Int(mynum/1048576)+1
wscript.Echo objDisk.DeviceID & vbtab & Myroundnum
End If

If objDisk.DeviceID = "I:" Then
mynum=objDisk.Freespace
Myroundnum=Int(mynum/1048576)+1
wscript.Echo objDisk.DeviceID & vbtab & Myroundnum
End If
Next