Have a client with the software installed on (1) PC only. This is in single user mode. It has been used for several months now with no problems. There are (2) company files which are maintained. When they tried to open one of them, this error message popped up:

"The company could not be opened. Please ensure the SQL sever exists, the service is running, and that the access has been granted." I have looked at all the instants on google I could find, but most were related to multiuser problems. Any suggestions?