How to read dynamic data from a USB port?

Hi,
I am new to C# and .NET, just started learning. My project is to read data dynamically from a USB port and plot it against time.

Now, I have the .dll file of the instrument connected via USB port.
Also, I had my own graph plotting application written in MFC and VS 6.0

when I try loading this application in MSVisual Studio 2005 using MFC application option it gives hell lot of errors. So I'm not able to use those classes and methods. Also I need to use VC# and VS2005 for the project.

Can somebody suggest me how do I read dynamic data from the USB port and have some idea about plotting them.

Please reply soon
Thanks,