Can't access "Network" and other performance issues

Question

Hi all,
I'm facing a catch-22 and am not sure what to do to get myself and my mac out of this downward spiral. Any help you can offer would be greatly appreciated (fyi I am admittedly not great with macs and probably don't maintain my MacBook Pro well enough).
I've had a serious slowdown in performance starting a couple weeks ago. the system moves at a glacial pace and most of the time is spent watching the spinning rainbow.
To add to my issues, my ISP recently performed a system upgrade which requires me to change some settings under "Network" in my system preferences. Well, when I try to access "Network", the machine thinks for a while, then an error message appears telling me that the network preferences has shut down unexpectedly. When I hit "retry" the error message eventually reappears.
So, because of the upgrade, I can't access the internet to download any repairs for the machine, and because of the problems with the machine, I can't modify the preferences to access the internet. Obviously a vicious cycle which someone of my expertise level is struggling to solve.
Side notes
- I've passed the 90-day phone support period so can't call for help.
- I'm on my work computer now. Could I download some repair/diagnostic tool here, then run it on my machine at home?
If anyone can throw me a lifeline I would be grateful!
MacBook Pro 15"   Mac OS X (10.4.3)  

Answer 1

OZ 99,
For logic's sake, I'm gong to take these out of order a bit:
2) A "disk error" occurs when the "file system" (sometimes called the "disk directory") becomes damaged. This is data that is written to the HD, so yes, it could be considered a software error. Your file system is, basically, a map of your physical HD, and it indexes the location on the drive of all the other files. When it is damaged for whatever reason, your disk "forgets" where some amount of data lives. Because of this, the associated files become damaged, or "corrupt." If those files happen to be critical components of the OS, bad things can happen. At worst, the disk will become unmountable, and all of your files unrecoverable.
1) Disk errors can be caused by several things. Sometimes, one or more "blocks" (let's call them physical locations on the disk) on your HD can become physically damaged. Whether this is because of a slight flaw in manufacturing, a scratch, magnetic particles that lose their "oomph," whatever, matters not. What is important is that some data is lost. Because the file system still believes there is data living in this location, it (the file system) is no longer reliable; it is damaged. While the initial loss of data could be considered hardware-related, the disk error is not. I'll come back to this.
Another potential cause is some random error in the process of writing data to the disk. Again, this is a software problem, not a hardware problem. The most common cause for this occurs when your computer is shut down improperly, either a forced shutdown or a power loss. Journaling, which is the default for an OS X boot volume, goes a long way toward automatically fixing these types of disk errors, but it is not always a guarantee.
If you have had your MBP for only a short period of time, it is not surprising that a disk error has occurred, and probably because of a bad block. Absolutely flawless drives are rare, and many computers ship with incipient disk errors. For this reason, many people like to format any new drive, even one in a new computer, right out of the box (I'll get to reasons why this is a good thing to do).
3) Yes. Disk Utility can check or repair your file system. Any repairs must be made using Disk Utility while booted to the OS X install disk. Your HD can be "verified," however, while booted to the HD. Simply open Disk Utilty (in the "Utilities" folder), select your startup disk, then click "Verify" in the "First Aid" pane.
4) Yes, you will have to reinstall all of your applications after formatting and reinstalling. Formatting erases everything on the volume or drive selected. Settings and data for all of those applications can be saved, however, then transferred back to the MBP after reinstalling OS X. Once the applications, themselves, have been reinstalled, you will be right back where you started. I can talk about making a comprehensive backup in another post, if you like.
DISK UTILITY: In my first post, I recommended that you select your entire drive, then using the "Zero All Data" option. This process takes a considerably longer amount of time (as much as an hour and a half, depending on the size of your drive), but it has one big advantage. When this option is used on an entire physical drive (also called a "device"), it will scan for those pesky bad blocks, and "map out" any it finds. Since these bad spots on the disk will not be included in the new file system's list of "useable" locations, your chances of encountering another disk error in the near future is drastically reduced. So, even though a bad block could be considered a hardware error, management of them is handled by software.
Scott