Connection to Database Dropping

We use SQL Express 2005 for a software program and after a recent update to the software, the database keeps dropping the connection. It's random on when the connection drops and it can be restored by rebooting the server or just the SQL Server (server name) service. In the Event Viewer, I get 2 instances of Event ID 5170, 1 of 17204 and 1 of 17207. Below are the descriptions of each error.
5170 Cannot create file 'g:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\ software_log.LDF' because it already exists. Change the file path or the file name,  and retry the operation. 17204 FCB::Open failed: Could not open file g:\Program Files\Microsoft SQL Server\MSSQL.1\ MSSQL\DATA\software_log.LDF for file number 2.  OS error: 32(The process cannot access  the file because it is being used by another process.). 17207 FCB::Open: Operating system ...