Thanks Bert for all the ideas. They will help when I give it a shot again. The main computer runs Win 7 Pro, the clients are 7 Home. I don't intend to "upgrade" from Win 7, ever. Have you written up before why you think that someone should not be working on the main computer? There is only myself--working on the main computer--and 2 client computers. Only one of the clients is in frequent use. I have done it this way for 10 years--since I started with Amazing Charts in early 2005.
Permissions and Windows firewalls are not the problem since the clients can connect to the SQL server on the main computer with the SMC router, but could not with the ISP's new modem/router. One computer could connect with the new router for some reason but the others couldn't. The clients could change files in the AC folder on the main computer too. I think that the problem must be in some sort of subtle networking issue like addresses. I have used DHCP on the router and the names of the computers. I keep things as simple as possible unless I have a reason to do otherwise.
The wireless modem/router is made by Actiontec
http://www.actiontec.com/217.html. (I don't want/need wireless but I share the network with someone who does.) I tried every way I could think of to plug the main computer and others into it--shutting off everything, turning everything back on, using a switch, plugging all computers into the router, etc. The router that works fine with AC is an older SMC Barricade model. I've read that I can access the new modem/router's firmware page, even though bridged, if I connect it directly to a computer with a fixed IP and then enter the router's IP address. I'm going to give that a try before physically reseting it to get it out of bridged mode.
