Ihave a brand new machine and have experienced unexpected (random) reboots too. The best I can tie it down at present is with Windows Movie Maker when attempting to retrieve DV from a camcorder in 7 or 8 attempts each time there has been a reboot after a period of 2 to 5 minutes.

Probably unrelated, I am experiencing random accessing of the floppy (A:) drive - similar to that which occurs during boot up. So far this accessing has not been associated closely with the rebooting problem other than the frequency of disk access is greater when I am downloading DV.

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