I can move the mousepointer, but it remains as the stopwatch and the OS is unresponsive.
Then the rest of the OS is ok and only the IDE bus hangs.
Could still be a power problem. What kind of HDD is it (2.5" or 3.5") and how is it supplied with power? Does it get power through the IDE cable (2.5" style) or is it connected directly to the power supply?
If 2.5", could you build a custom cable which connects only the data lines to the motherboard and the power lines to the power supply?
I have a spare PSU that i can try with when I get home from work. But it is so strange that the HD should "work" when booting from the OS3.1 install-floppy, but not when booting from the HD and not when booting from the WB3.1-floppy.
I suppose that it depends on the amount of data which is transmitted over the IDE cable. And (if it is a power problem) on the number of head movements or such.
Do you have a spare IDE cable which you could test, too?
Do you have a spare HDD which you could try? Preferably a more modern one which needs less power or even a CF or SD card with a matching IDE-Adapter.
SnoopDOS won't be of much help. It will probably stop at an Open() of a certain file. You could only find out if it always stops at the same file and compare this to the same operation on WinUAE. But if WinUAE does not stop at this file, then the information is of no use.
If it's always the same file, then you could use WinUAE to delete it and see if it becomes better on the real Amiga. If this works, a virus comes into mind as another possible reason for all the trouble.
Edit: one more idea. While the drive is connected to a PC, can you use a Windows tool to read out its SMART data? Perhaps it has some health problems which are not so severe for Windows.
