Solved. Toronto power failures.When I was having trouble Toronto was nearly 30 below and windy snowstorms and ice. I did not realize that my area of Toronto was having brief power failures.
The Seagate...turns out it was not the problem. I had it plugged directly into computer USB as always, but the separate power source was a surge supressor power bar which kept shutting off and turning on. It was sporadic power failures for several days from extreme weather which repeatedly forced partial reboots of the Seagate without me realizing what was going on. The computer stayed on because it has battery and power.
The Seagate was not the problem and works perfectly now.
2 days ago I just bought an HP EliteBook Workstation which had Windows 10 and had my techie change to Windows 7, so I now have the XP and Windows 7. I have many thousands invested in printers,
software and hardware which either no longer exist or would cost thousands to replace. Wacom Tablets and countless software for Publishing and architecture.
I was having unpredictable power flashes and failures in Toronto from 30 below storms. I had not noticed constant shut downs with the Seagate. My bedroom has two clocks, one battery, but the other was plugged in....and the time showed it had reset to 12 and started again. The Seagate worked perfectly when the power became stable. The good news, my new HP Terabyte...recognized it, and I slid my mouse steadily through all the files, and pasted into the empty brand new terabyte hard drive. It took 2 hours but what amazing technology.
I am an author and digital artist, and it would cost me countless thousands to replace printers, 18 inch Wacom Tablet, and all the Digital Art software and genuine architecture programmes,...etc. if I go higher than Windows 7.