Related to your question, you may want to consider limiting the amount of RAM SQL Server has access to if you are using it in a shared environment, i.e., on a server that hosts more than just SQL Server:
- Start > All Programs > Microsoft SQL Server 2005: SQL Server Management Studio.
- Connect using whatever account has admin rights.
- Right click on the database > Properties.
- Select "Memory" from the left pane and then change the "Server memory options" to whatever you feel should be allocated to SQL Server.
This will help alleviate SQL Server from consuming all the server's RAM.