If you want to repair or improve your photos, the best way is with photo editing software, and the best photo editing software, in my opinion, is Adobe Photoshop. It is the one piece of software that comes to mind when considering editing photography.
My experience with Photoshop goes back several years. When I was in film school I used Photoshop on a regular basis. As a professional photographer I relied heavily upon Adobe Photoshop.
It is what professional photographers use around the world, but it is just as easy for the consumer to use. The software is easy to learn.
I took a couple of classes on Photoshop in film school, but the same can information can be found in several books (Found at your local library), or on the web. There are many tutorials out there. All you need is a little patience and basic computer skills and you can learn Photoshop well enough to make your pictures look better.
I have always used Photoshop as a part of Creative Suite. Creative Suite is a package that includes several pieces of software. There are several different versions of Creative Suite. Each version includes a different assortment of software.
The version that I recommend is Creative Suite 5.5 Master Collection for Mac. This versions includes: Photoshop, Illustrator, InDesign, Acrobat X Pro, Flash Catalyst, Flash Professional, Flash Builder, Dreamweaver, Fireworks, Contribute, Premiere Pro, After Effects, Audition, OnLocation, Encoure, Bridge, and Device Central.
I shall not go into detail about each piece of software included, but to say, with this collection you can do the following: edit video, edit sound, edit photography, design a web site, and more.
It is also available for the PC, but if you are working with graphics, photography, etc., it is best to work on a Mac. They are better at dealing with graphics than PCs.
You can also get Photoshop as a stand alone software but the suite is what I suggest if you can afford to buy it. The suite goes for just under $2,250 on the B and H Photo and Video web site. You may be able to find it cheaper somewhere else on the web, but those prices change often depending upon sales and deals.
With Photoshop you can take the old photos you have in storage and make them look new again. You can turn a black & white photo into a color photo. You can remove scratches.
Photoshop also allows you to change the appearance of your photos. You can remove blemishes on portraits. You can crop photos in Photoshop better than in any other software. You can do what professional photo editors do by simply reading a few books and watching some tutorials found on the web.
I know that Photoshop is not for everyone. You do need to know some basic computer skills to use Photoshop and you need to study some before using it to its fullest. But it is relatively easy to learn. After you learn the basics you will want to keep going. With even the basics you can do some fun and creative things with your photos.
The first thing to consider is whether or not you want the advantages of the Creative Suite or if you just want Photoshop. My suggestion would be to buy the Creative Suite: Master Collection.
The second things to consider is whether you own a Mac or a PC. If you do not own a Mac you should consider purchasing once since they handle graphics better.
You also want to use your search engine (Yahoo!) to search and compare the different places where you can purchase it. Since the prices for most of these sites change on a regular basis I have linked to the B and H Video web site, which is the most reliable source for Photography and Video equipment.
My basis for these opinions are my personal experience with the software and my professional experience with the software. I am a professional photographer, so your results with this software may vary.