The pages on this site contain documentation for very old MS-DOS software,
purely for historical purposes.
If you're looking for up-to-date documentation, particularly for programming,
you should not rely on the information found here, as it will be woefully
out of date.
SYS1830
SYS1830Explanation
The mouse may not be installed properly.
Action
Check that the mouse software is properly installed. Then restart the
system.