I have a question, I need a stock for a signature.

I went on google images, searched what i needed, saved and opened the image in photoshop.

I cropped the image, and used the eraser and erased everything around my image so its all white.

I then saved and dragged the image into my background.

My background was finished and just needed an image, but when I dragged my image into my background the image came out but surrounded with a white box that i made when i erased everything around it.

my question is, how do i remove this white box around my image so only the image shows on my background instead of the image in a white box?

i know this has something to do with rendering.. how do i do that using photoshop cs?

thanks

if its all white, it should be easy just to:
Click and hold on the eraser button and you'll get a small drop box, you shall see magic eraser tool, thats the one you want, click on the white background, and when everything is selected press delete.
you should end up with just the render i think

Usually you have to render the sig.
Open your picture, duplicate layer, make new layer.
Make sure your new layer is above the stock and the stock is under the duplicated layer I believe.
Get your pentool, select paths, go around the entire image.
When you are done, right click, make Selection, Inverse, and Delete.