I have a photo cd made on Windows XP and would like to convert it to a/vista file to view on Windows Vista.

If the files are the typical JPEG (usually with the .jpg extension) from a digital camera and recorded in a single session on a CD-R the Operating System (OS) shouldn't make a difference. Such files are even compatible with Macintosh computers and many DVD players.

The potential for trouble comes with the packet writing software that allows a CD-RW disk to be used like a hard drive. There are multiple publishers of packet writing add on and the resulting media isn't always compatible with other publisher's packet writing software. Where a transfer is necessary between computers with different packet writing applications the source computer should be used to generate a regular CD-R, write on a CD-RW in the formating normally used for CD-Rs, use an external USB hard drive or a USB flash drive.

Robert is right on. So you need to explain what problems you are having in reading the disk. It has little if anything to do with Vista vs XP.