It could be "copy protection" on the photo, the scanner, or its driver.
I have seen similar results when trying to scan a photo I purchased from NYRR after completing my 1st NYC marathon. Since the photos were taken by a professional, and sold to me, they didn't want anyone making copies of them. I'm not sure what is is in the photo that messes with the scanner.
That said, if it's an old scanner, the lamp or CCD may be just wearing out. I wouldn't waste money trying to fix it, since a new scanner that is faster and higher quality and doesn't cost all that much.
Try scanning other photos and images. If they all look similarly bad, then buy a new scanner. I like the Canon brand as well. Seems to be good quality, and decent software. Also, high-speed USB will make a huge difference in scanning speed, assuming that your PC has USB 2.0 capability.
FW