Why do you need a Symbol Server?
Microsoft Symbol Server is a Windows technology used to obtain symbol debugging information.
It is built by using the SymSrv technology that is bundled with the Debugging Tools for Windows package.
You can use a symbol server to allow Visual Studio to automatically download the correct symbols for debugging your Visual Studio project.
Microsoft maintains public symbol servers that provide symbols for Windows operating systems, in addition to MDAC, IIS, ISA, and the .NET Framework.
Visual Studio 2008
Microsoft Visual Studio 2008 SP1 connects to the Microsoft public symbol servers automatically when you click Load symbols from Microsoft symbol servers in the Options dialog box (Debugging category, Symbols page) or the shortcut menu (in the Modules Window of Call Stack Window).
In addition, you may have a local symbol server set up on your Intranet or on your local computer for developers at http://msdl.microsoft.com/download/symbols.
If you have Visual Studio 2008 SP1, you can remove paths from the Symbol file (.pdb) locations list in the Options dialog box.