Just a BIG suggestion here with a suspected hard drive problem:
1. Backup
2. Backup
3. Backup
4. Backup (Am I stressing this hard enough!)
Now, I try not to be critical of software utilities. However, from bad past experiences & other internet user complaints and suggestions, maybe your problem is not the hard drive but a Norton problem. This is just a guess on my part.
First thing is ask yourself if you have heard any strange noises coming from the drive or is it acting strangely. Second, ALWAYS keep a hot backup handy just for emergencies. Third, try Apple's disk utility to see what it says.
Here is IMHO the most reliable drive utility is called
DiskWarrior. It will always set a screwed up system straight as an arrow.
Also, on the flip side, IMHO the best backup utility is called
Carbon Copy Cloner.
Lastly, an OS X user should, on a regular basis, Repair Permissions using Apple's Disk Utility (Applications->Utilities-Disk Utility). After all, OS X is based on BSD Unix. doing this on a regular basis will prevent a lot of headaches along the upgrade way.
So, Good Luck on your problem.