Try Control Panel > System > Hardware > Device Manager
or
Right click the My Computer icon, select Properties > Hardware > Device
Manager

Try right clicking on the My Computer icon on your desktop and selecting
Properties.  Do you still see no Device Manager tab?  What happens if you open
the Run box (Start | Run) and enter
rundll32.exe   shell32.dll,Control_RunDLL   sysdm.cpl
and click OK.  Does this open System Properties?

If you are still unable to access the Device Manager check that you have the
file sysdm.cpl in the windows\system folder.

If nothing works or sysdm.cpl is missing you can extract a new copy from the
Win Me cab set.

sysdm.cpl is contained in WIN_9.CAB of the Win Me cab set and can be replaced
by booting to Safe Mode and using MSConfig | General | Extract File and
following the prompts.  The "cab" files are in the Win9x folder on the Win Me
CD and normally also in either Windows\Options\Cabs or
Windows\Options\Install.  See MS  KB 265371 - "How to Extract and Replace a
Protected File in Windows Me" (http://support.microsoft.com?kbid=265371) for
details of how to extract files from the cab set.

sysdm.cpl  belongs in the windows\system folder.