I have three different external usb hard drives that I sometimes connect to my pc. All three have their own power supplies. Recently, when trying to write data to any of these drives the pc freezes. No BSOD, no error message. It just freezes with what ever was displayed on the screen. Only way to recover is hit the reboot button on the front of the case. The only big change to my pc recently is install of SP3, but I don't recall if these problems started just before or just after installing SP3. If not related to SP3, any ideas what might cause this problem?