I wouldn't put any Norton product on my drives in X. It's caused a lot of problems for people.
Use DiskWarrior if you have it.
Run fsck on your disks to check them.
To run fsck, you first need to start up your Mac in single-user mode. Here's how:
1. Restart your Mac.
2. Immediately press and hold the Command and "S" keys.
You'll see a bunch of text begin scrolling on your screen. In a few more seconds, you'll see the Unix command line prompt (#).
Congratulations.You're now in single-user mode. I bet you've never seen your Mac screen look like that before. (I wish I could show you a screen shot of it, but as far as I can tell, it's not possible. And photos of it are ugly.)
Now that you're at the # prompt, here's how to run fsck:
1. Type: "fsck -y" (that's fsck-space-minus-y).
2. Press Return.
The fsck utility will blast some text onto your screen. If there's damage to your disk, you'll see a message that says:
***** FILE SYSTEM WAS MODIFIED *****
If you see this message--and this is extremely important--repeat Steps 1 and 2 again and again until that message no longer appears. It is normal to have to run fsck more than once -- the first run's repairs often uncover additional problems..
When fsck finally reports that no problems were found, and the # prompt reappears:
3. Type: "reboot" to restart,
or type "exit" to start up without rebooting.
4. Press Return.
Your Mac should proceed to start up normally to the login window or the Finder.
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You can also leave your machine on all night and the built in maintainance routines will run automatically. Just set not to sleep the hard drive.
I leave mine on 24/7, but you could just leave in on one night a week to run.