Issues w/OS X Leopard. Ok to install Snow Leopard?

Hi everyone!
Can somebody advise me, please...?
I own a Black MacBook 4,1 (late 2008) with OS X Leopard (v.10.5.8) installed. I am experiencing problems with the hard drive, which requires the Installation Discs to sort it out, but I don't have the Installation Disc Set.
I was wondering what would be the best, most effective remedy for this problem? Would it be possible / recommended to backup then format the hard drive and do a fresh, full install using OS X Snow Leopard 10.6? Would this be possible and would it sort out the problem/s?
Many thanks in anticipation.
Sincerely,
Nigel.
P.S. I'd also like to say a big "thank you very much!" to all those who responded to my initial/first call for assistance concerning my new external hard drive.

You could use a Snow leopard disk to boot and repair the disk and then proceed to do a fresh install, that would be fine

Have you got all your files off the disk first?, if not try a disk repair first, and since Snow leopard disks are inexpensive that would be your best bet