If you don't like the above try this from the autodesk knowledge base. Should work for 2000,2000i and 2002.
Issue
You want to insert a block so it is unable to be exploded, making it impossible for users to edit the individual objects in the block.
Solution
You can use the MINSERT command to make a block that cannot be exploded. The MINSERT command is typically used to insert multiple instances of a block in a rectangular array. Blocks inserted using MINSERT cannot be exploded. The MINSERT command is only available from the command line.
Note: Before trying the following procedure, make a copy of the drawing you want to protect.
1. Start a new drawing from scratch.
2. Enter MINSERT on the command line.
3. When prompted for the block name, enter the drive letter, the full path, and the name of the drawing you want to protect.
Example:
MINSERT Enter block name or [?]: D:\AutoCAD\SAMPLE\campus.dwg
4. Enter 0,0 for the Insertion point.
5. Use an X and Y scale factor of 1.
6. Specify a rotation angle of 0.
7. When prompted, specify the number of rows and the number of columns to be greater than. If you specify only one row or column, this command is treated as an INSERT command and a user will be able to explode the block.
Example:
Enter number of rows (---) <1>: 2
Enter number of columns (|||) <1>: 2
8. Specify the distance between rows to be 0 units.
Example:
Enter distance between rows or specify unit cell (---): 0
The block will be inserted into the current drawing. You can erase the inserted block, but you cannot explode it.
Rick Kitson MBA P.Eng
Construction Project Management
From conception to completion