All custom toolbar definitions are saved in the Menu source file (*.MNS). It will have the same name as your menu file but it will have an MNS extension (The menu file has a MNU extension).
For example: I run Mech 2004 and my menu file is named: ACADM.MNU and my menu source file is ACADM.MNS -- I am not familiar 2000 mech so your filenames may different.
When you find the files, FIRST, make a copies of both the MNS and the MNU file. This will protect you incase you make a mistake.
At this point you can either try to load the *.MNS file or you can open both files (with notepad) and copy the **TOOLBAR info from *.MNS file over to your *.MNU file.
Load the MNS file by typing in MENU at the command prompt and Browse to the *.mns file.
If you decide to edit the MNU file, you can load it the same way.
Let us know if that works for you.
Regards,
Joey Steed