Machine iMac g5.osx 10.4 Purchased August 2005. Since that time the hard drive has been replaced and I have had to re install operating system three times. All for the same problem. Machine will freeze. I turn off. Re start, machine will not load operating system Run utilities disc, machine shows no hard drive. Advice received from Mac support was to erase and re install. This I do with no problems, except I have lost my programns and information. This may be coincidental but just prior to each freeze I noticed that Safari had disappeared from finder and yesterday just prior to freeze my Word processing had disappear. Advice now from Apple is to bring machine to service shop. This involves a rather lengthy trip on a bus, since machine now is operating, shows no symptoms, Disc utilities show no problems, I am unsure as to what that would benefit as the system was erased yesterday and operating system re installed. Problem seems to happen approx every 10 weeks