i used a scrollbar in my panel. but when i scrollup or down the panel flickered.

Upload a sample project demonstrating the behavior

sorry i didnt got u
upload.... from where

When you answer to a thread, look below the buttons Submit Reply and Preview post. You'll see a panel marked "Additional Options". You will find a button there : Manage Attachments click on it, it should be obvious now...

where is the sample project. i m unable to get it

The sample project is the project you are having trouble with. As sknake did not know the name of your project he called it "sample project". You could preferably zip it before uploading.

>It runs OK up to the point where it could not find the file "e:\\CuPeak.dat".
As I don't even have an e: drive, this is going to be difficult...

i have attached the txt file and also changed the path to c. i want to zoom the to any extend and use the scrollbar(both horizental and vertical) to see it

Remove this line from your Button1_Click handler:

g.FillRectangle(Brushes.Black, new Rectangle(0, 0, pnlGraph.Width, pnlGraph.Height));

Fill in the BackColor property of your panel in design mode. Maybe it's not much, but it helps if the background of your panel is already black, instead of having to repaint it every time from white to black.
Also the line pnlGraph.Invalidate(); near the end of the same handler is not needed.
I was also wondering why you have to change an integer value to a float value. This causes extra overhead, which, perhaps, is not needed.