My powerbook 667 has been acting very wierd lately. The hard drive is constantly clicking now as if its acessing the hard drive. Safari has lost two of my bookmarks on the bookmark bar( not at the same time). My time switched from regular time to military time without me changing it. And it sometimes beeps out of the blue, kind of like a higher pitch sound of a phone dial. The last major change to my computer has been an upgrade to 10.2.4. Any ideas what it is?