Another possible cause for corruption can be by taking the memory card out of the camera before it has finished saving the files to it. This has been overcome in a lot of newer cameras but you should always make sure that the camera is turned off first.
By formatting your card you do a clean wipe of the card and
start fresh. Generally this means that no photos can be recovered although my Minolta Dimage 7i seems to go against that theory.
To format your card, first make sure that all the pictures you want to keep have been saved to your computer or to CD or DVD. Then check your manual for where the Format Command is hiding in the menu system.
I just looked where I thought mine would be and it was in a totally different spot. Generally though it’s in the replay menu. Go to Format Card and say yes. It will only take a few seconds and will give you a fresh start
By the way if your card does become corrupted, stop using it straight away and take it to a photo lab who will in most cases be able to recover the photos from it. Software is also available to do it yourself but for the price it is cheaper to use your photo labs expertise and they will generally have a number of different programs available to them.