Your question is a bit confusing, but if you wish to draw a circle, much kike one would do with a pencil then do the following:
Use Blueark's instructions for selecting the eliptical marquee tool
Use Jimoblak's instruction "(Hold the Shift key while using this tool will create a perfect circle)".
After creating the circle outline (you will see the crawling ants) click Edit, click Stroke, choose the width
(5 pixels is a decent start), choose "outside" for location, Opacity (100%) and mode (normal), then click OK.
After that you can start over and choose the stroke settings anyway you wish.
Much Luck