Convert PNG to icon - repost

Please find attached a zip that contains different size versions of the same image in PNG file format (with transparent background). Your job is to convert the image as Windows icon file (.ICO) in a way it is shown properly without any jagged edges in Large Icon View in Windows Vista and newer. You can use the version with the shadow or without, whichever looks better. Note: You cannot do this job by simply opening the PNG in Adobe Photoshop and selecting Save As > .ico. If it was that easy, I could do it myself.