Tony ... SQL Server is designed to dynamically manage the memory on the server. Assuming no other processes, it will leave the OS about 5 meg. Then, as the server needs it, it will dole it out. You can modify these settings either thru Enterprise Manager (Server/Properties/Memory) or QA (sp_configure).
From BOL under memory -> dynamically managing
[QUOTE] Dynamically Managing Memory on Windows NT and Windows 2000When running on Microsoft® Windows NT® or Windows® 2000, the default memory management behavior of the SQL Server database engine is not to acquire a specific amount of memory, but to acquire as much memory as it can without generating excess paging I/O. The database engine does this by acquiring as much memory as is available, while leaving enough memory free to prevent the operating system from swapping memory.
230MB is almost nothing in the SQL server world. Maybe it is OK for a dev machine, but certainly not a production server. What is the problem you are trying to solve? And what proof do you have that this solution (if it works) will solve that problem?
As for the question, you could try to set auto-close on the user databases. This will close the database files, but I am not certain if it will release any of the memory.