As TheEnigmaticT says a smaller partition would be the simplest solution.

However it doesn't have to mean re-partitioning. At least in Windows 7 (not sure if Vista is an option)

1) I've made a VHD file through Computer Management->Storage->Disk Management->(Right click) Create VHD.

2) Mount the drive (make sure it's smaller than 2TB

3) Install or move the game to the new virtual drive.

4) The drive doesn't mount at system start up. So if you want write down these two scripts :

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' Argument from command-line
strFile = WScript.Arguments(0)

Dim objShell, objFSO, objFile

Set objShell = CreateObject("WScript.Shell")
Set objFSO = CreateObject("Scripting.FileSystemObject")

If objFSO.FileExists(strFile) Then ' Check to see if the file exists
Set objFile = objFSO.GetFile(strFile)
strCmd = "powershell -nologo -command " & Chr(34) & "&{" & objFile.ShortPath & "}" & Chr(34) ' Chr(34) is ""
objShell.Run strCmd, 0 ' 0 hides the window
Else
WScript.Echo "ERROR: " & strFile & " does not exist." ' Display error message if file does not exist
WScript.Quit
End If

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Save it as silentpowershell.vbs (used to wrap the next script and prevent pesky powershell prompts popping up while logging on.)

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function Mount-VHD
{
<#
.Synopsis
Mounts a VHD file
.Description
Mounts a VHD file with diskpart
.Example
Mount-VHD .\this.vhd
#>
param(
# The file to mount
[Parameter(Mandatory=$true,ValueFromPipelineByPropertyName=$true)]
[ValidatePattern('\.vhd$')]
[string]$File,

# If set, makes the VHD read only
[switch]$ReadOnly
)


process {
$resolvedFile = $ExecutionContext.SessionState.Path.GetResolvedPSPathFromPSPath($file)

if (-not $ResolvedFile) { return }

$diskpartScript = "
select vdisk file='$ResolvedFile'
attach vdisk $(if ($readOnly) { 'READONLY' })
"
$diskPartScriptPath = "$env:Temp\DiskPart.$(Get-Random)"
$diskPartScript | Set-Content -Path $diskPartScriptPath -Encoding ASCII
diskpart /s $diskPartScriptPath
}
}

Mount-VHD "X:\VHDDIR\VHDFILE.vhd"

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Save it as automountvhd.ps1 (Remember to change the path and file name at the bottom.)


And finally create a Task in Task Scheduler Library add this

Program/script: wscript
Add arguments (optional): "X:\path-to-script\silentpowershell.vbs" "X:\path-to-script\automountvhd.ps1"

And again change paths and file names to what you have.

Finally make sure the Task runs "At log on"

P.S. This works for all the Infinity Engine games which cannot start whenever the drive you have installed it on is 2TB or larger.