I'm using VS2005 & SQL Server 2005 which is installed with VS2005.
Platform is XP SP2.
I've an app that connects to the DB & get some data from it .
The app & DB are on the same machine .

Suddenly When I run the app. , I've that error :


I've searched over the net for that problem & I've done what others did:
1- Enable Remote Connection:Using both TCP/IP & named pipes.
2- Maker sure that the service is running .
3- Add exceptions to the firewall
Then after that ,I'm still facing the same problem .
After all trials ,I've uninstalled VS2005 & all it's component .
After installing it again ,I've the same problem .

So the Solution is ....?!!

if your sql server is running on the same box, it won't be a firewall issue, it sounds like you need to check your database permissions. check what account you have visual studio running under and enable this as a user for your database.

First ,Thanks adamm4.
Second ,I'd discouvered that the problem in the connection string . specifically in the Data Source ,althouhg , I copied it from the Conn Str prob. & it was working before.
All what I've done to make it work again is to but \\ rather than \ in the Data Source .