Sorry but its not Accessible as stated:
In Windows Vista, progressbars come in different flavors, the most
common progressbar being the green one. However, there are also the
red and yellow versions as well (there is a blue version, known as a
meter, but that is inaccessible). The progressbar colors seem to
correspond to specific progressbar states. You can set these states
using the PBM_SETSTATE [0x40F] message. The states are PBST_NORMAL
[0x0001], PBST_ERROR [0x0002] and PBST_PAUSE [0x0003].
But if you are interested it is possible to access the Red and Yellow Color
using the following:
Declare Auto Function SendMessage Lib "user32.dll" (ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
Enum ProgressBarColor
Green = &H1
Red = &H2
Yellow = &H3
End Enum
Private Shared Sub ChangeProgBarColor(ByVal ProgressBar_Name As ProgressBar, ByVal ProgressBar_Color As ProgressBarColor)
SendMessage(ProgressBar_Name.Handle, &H410, ProgressBar_Color, 0)
End Sub
Example of Usage:
ChangeProgBarColor(Progress_Bar, ProgressBarColor.Red)