1 macs cant its not in there coding. xp and vista do blue screen very rarely, Its mostly do to hardware failure, which IS no way in any shape Microsoft's problem. Or if key system files are damaged. Always caused by user error. However Macs will either not power up or stay at a grey screen for ever leaving the end user clueless.
2 either system can do that. In Windows its normally caused by user error. Macs caused by programing incompatibilities or user error
3 viruse are user errors. I have never recieved a virus. I use AVG Free omce a month and its always clean. Use firefox and common sense and you will never get a virus. there are viruses for Mac, more classic though like false icons and constant ejecting of CD's. There is a one that will delete system files though.
4 each computer is different you cant compare a celeron PC to a core 2 duo Mac. Irrelevant. Cost is a factor to. Vista is really good at telling you what is wrong now. As for Mac im not sure.
5. Irrelevant. If a HDD fries its a Manufacture's fault in QA. either, Maxtor, Seagate, Samsung, Western Digital, Hitachi, Toshiba, etc. No virus can cause hardware damage. they can format a drive and even than run Recover my files and presto all the data that "fried" away i back.