You can check if it is already in your browser or not by:

• Click "Favorites" on menu bar of your browser.
• Click "Organize.." (or "Organize Favorites") that will bring a new pop-up window.
• Click "Links" folder and see if there is a word "JustSnipe!" under this folder.

-- If yes, it means that you have added the button already but it might not be visible. You can drag the word "JustSnipe!" to the top list under "Links" folder. Then, make sure that you have turned on the "Links Bar" by clicking
"View" -> "Toolbars" -> make sure that "Links" is checked.

-- If no, it means that you have not added the button. So, follow the instruction on http://www.justsnipe.com/auctions/tools/presnipe_intro.asp