Some may think that with all the Macs I have written about over the last few years, everything works perfectly. My own Macs have all behaved well. My first modern Mac which I bought in early 2002 still performs sterling duty in the hands of a friend. After three years great service from my 2.16Ghz MacBook Pro it was an easy decision to move to the current 2.66GHz version with the i7 processor.

The first four months were great: I revelled in the improved speed and graphics. In late July things began to go wrong. While working, the cursor would stop moving and the computer would freeze, leaving me with no choice but to shut down using the power button: not recommended.

Logs suggested that the NVidia graphics may have been at fault. I consulted Dr Smoke: figuratively and literally. As well as looking through his online information, and the PDF, "Troubleshooting OS X", we used email. Over the last couple of years we have occasionally chatted about OS X and other matters. I am grateful for his help, especially in examining the logs. One thread on the Apple Forums has more than 60 pages of user postings on this behaviour.

I could not make repairs initially because the firmware password was on. This can now only be unlocked with the installation disks which were safe at my office. Once I had the disks, I tried Dr. Smoke's main suggestion which was to reset the NVRAM (non-volatile RAM). This is done nowadays by resetting PRAM (parameter random access memory): holding down the Option + Command + P + R keys at startup and letting this cycle a couple of times.

Using the software install disk, I also ran the extended hardware test (start with the D key pressed): there were no problems. For a day or so, all was fine, and then the gremlins returned. Whatever I turned off (or on), within a short while the screen would freeze; and the dog would know it was time to hide again.

By Monday morning just after looking at Aperture (photography workflow software) another freeze occurred. I tried resetting PRAM and, just for luck, ran the file system check which turned out to be the nail in the coffin. It would not come out of this and I was left with an almost dead Mac. I can work with basic Unix, but no amount of repairing returned me to OS X.

I did have access via Target mode, however, and spent a frantic afternoon moving data onto the Mac mini that was still in my hands. I also contacted EITS, from whom I had bought the machine and Khun Pornpen arranged collection for a possible warranty claim. I later cancelled this.

The setup with the mini was temporary and I was not able to transfer all the data in the brief time I had: mail accounts were not working in Mail and bookmarks were missing. If the Mac mini had been mine, I would have spent more time on this. I do have an iMac upstairs, so that was another option: the transportability of the mini meant I could easily carry it to work.

I took the bull by the horns at home and put in the OS X install disks. The process is different now and, unless one wipes the disk, the reinstallation preserves the disk contents, similar to the former Archive and Install. When the Mac restarted, I breathed a sigh of relief when I saw the two accounts: Admin and User.

After the new OS X was installed, I knew that I still had to bring it back up to version 10.6.4 but as the system thought it was new, Spotlight was busy indexing the data. Once done, I copied the 10.6.4 Combo update to the Admin account and restarted the computer: the combo includes all the updates of 10.6.

All well and good: and as I made my way round the computer, everything seemed ship-shape. However, when I later connected the iPhone, it did not appear in iTunes. We had been down this road before, when I first bought this Mac, so I was ready for the process. I was lucky this time and installing iTunes (9.2.1) over the top of the same version did the trick: the phone was recognised when I next connected it.

When recording the eXtensions podcast 24 hours later, however, another freeze occurred. This was followed that evening and the next morning by several more, but I did notice that the Dock was being used most times. I deleted the Dock preferences (.PLIST) file and stability returned. I then went back and pinpointed the date it all started and saw that I had downloaded QuickTime 7. And initially I had the wrong version. I removed the related preference files for that too and stability returned.

Although I am back with a working computer, I am on edge and watching carefully.

Update: It looked as if I had cured the problems when I submitted that to the Post, but a few days later, there was the occasional freeze again. This went from bad to worse until I backed up what I could and wiped the hard disk. A completely new installation of OS X, Snow Leopard, was no better and I must conclude that the problems are hardware-based: a warranty claim methinks.