Im developing a accounting vb.net windows application,
1.In this 1 company can be created with its customer n vendors. My problem is how to make multiple companies...for ex in quickbooks and many applicaiton when application starts it asks like select company..on selecting company we can add details related to that company only. If anyone knows what actually happens...Im fresher and I dont know what they are doing or what can be done...

2.If i want to install it on client side what about database n server settign...Im making 1 form for server setting but is it actually needed or any other good solution...bcoz if client changes sa pwd or has anytoher user how can the db connection changed in my applicaiton as im saving that in app.config

Any suggestions are welcome!!
Thanks