Sorry for the delayed reply. You can design the table with column name "Company name" based on the company name... you can filter the datas....
Just tell us whats your problem instead of typing a lengthy post
Good basics
I think server.transfer will avoid a round trip from client to server
Null is referred to as nothing and it can be assigned to varchar or string variable and also to int where as 0 is the value assigned to int
Its nothing but a function which can be overridden in the sub class
You can search in wrox.com or go with some file sharing site
Separate names with a comma.