Not enough information given ....

We really do not have enough information here. You didn't tell us what form the photos were stored in (JPEG? TIFF? some camera specific "RAW" format?), or how you stored the photos (what software wrote the photos to the drive) or what software you are now using to retrieve and view the photos.

But first, a bit of background:

A computer file (ANY file, of ANY type: program, document, spreadsheet, photo, video, song .... ***ANY*** file, period) is just a list of numbers. That's all that any computer file is. All of the numbers are between 0 and 255, comprising what, in the computer world, is known as one byte. If you have a one-megabyte file, then there are approximately 1 million numbers in the list, that being the length (size) of the file.

The only thing a hard drive does is store those lists. And the hard drive has extensive error detection and checking so that, if it cannot ACCURATELY retrieve a file (e.g. with ZERO errors ... ZERO, period; even 1 error in a BILLION bytes is totally unacceptable), it at least KNOWS that it didn't retreive the file accurately (e.g. that whatever it did retrieve may not have been what was originally recorded) and you will be informed of that fact. I'm not saying that the hard drive is infallible, but I am saying that if it does fail (and they do, most definitely), you will KNOW IT and be told ... explicitly. The one thing that will NEVER happen is a hard drive reading a file back differently than what was originally recorded and not KNOWING that it was at least possibly different.

The problem here is not the hard drive. If you are not getting "file read errors" (and believe me, you would know if you were), the hard drive is retreiving the same "list of numbers" that it originally stored ... when the files were written.

So something else is going on. But from the information given, there is almost no way to know exactly what. The most likely answers are that the bars were there when the photo was saved (in whatever unknown format) to the hard drive as many as 8 years ago. In other words, if you had done the EXACT same thing in 2002 or 2003 that you are doing now ... you would see the same result. Note that "doing the EXACT same thing in 2002 or 2003 that you are doing now" might have been physically impossible, because you might be using software today (to read or view the files) that didn't even exist in 2003. Which, in fact, is one very possible source of your problem: A software incompatibility between the software that you were using 8 years ago in 2002 (when the photos were taken and stored on the hard drive) and the software that you are using today in 2010 to retrieve and view the photos.

Beyond that, I can't help you any further without a LOT more information.