I think this is a setting for you--not the pc.

But if you open a workbook that's shared (looked for Shared in the title bar),
then there's an bug in xl2k that turns it off.  (It was fixed in xl2002.)

If that's the case...

Saved from a previous post...

Is the workbook shared?  (A bug in xl2k turns it off for shared workbooks.)

You could create a new workbook saved into XLStart (or put this into your
personal.xls workbook) and it'll toggle that option each time you open a
workbook.

In the ThisWorkbook module:

Option Explicit
Public WithEvents xlApp As Excel.Application
Private Sub Workbook_Open()
   Set xlApp = Application
End Sub
Private Sub Workbook_Close()
   Set xlApp = Nothing
End Sub
Private Sub xlApp_NewWorkbook(ByVal Wb As Workbook)
   Application.ShowWindowsInTaskbar = True
End Sub
Private Sub xlApp_WorkbookOpen(ByVal Wb As Workbook)
   Application.ShowWindowsInTaskbar = True
End Sub

If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm