A client recently struggled when his XP workstation's left pane disappeared. This pane contains commons tasks such as emailing files.
A simple registry modficiaton was needed to remediate the issue:
Windows Registry Editor Version 5.00[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]"WebView"=dword:00000001[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]"ClassicShell"=dword:00000000
After applying the fix, I killed the explorer.exe
process, then re-opened it. The pane was now visible.