Count down in For...Next loop?

[emendelson]

This should be obvious, but I can't find the answer anywhere. I have a For...Next routine that counts from ASCII 65 to 90 to find free drive letters, starting with A: and ending with Z: Is there a way to make it count down from 90 to 65, so it will start with Z:?? This is the code I use:

For $x = 65 To 90
        If DriveStatus(Chr($x) & ':\') = 'INVALID' Then
            $firstFree = (Chr($x) & ':')
            ExitLoop
        EndIf
Next

Thanks for any advice. Again, I think the answer should be obvious, but it isn't obvious to me.

[Nine]

If DriveStatus(Chr($x) & ':\') <> 'INVALID' Then

 

[Andreik]

For $x = 90 To 65 Step -1
   ...
Next

 

[emendelson]

31 minutes ago, Nine said:

If DriveStatus(Chr($x) & ':\') <> 'INVALID' Then

 

What I'm looking for is a drive letter that is NOT currently in use, so that I can assign it as a drive letter in a DOS emulator (DOSBox or vDos), which is why I needed  = INVALID.

[emendelson]

17 minutes ago, Andreik said:

For $x = 90 To 65 Step -1
   ...
Next

 

Thank you! I guessed that the answer was simple, but I simply didn't know what it was. Perfect!