Thanks so much for all this, and sticking with it.
Just to let you know where I am now.
I had already used scanreg to restore previous backups of the registry when I was experimenting with this much earlier on. It is an excellent facility which has saved my bacon several times over the years, and it's always puzzled me as to why NT based systems don't have it. Maybe the backup files would be too large or something.
I have a Windows 98 Resource Kit utility which allow parameters such as the number of backups and which files are backed up to be changed using a graphical interface.
I expect you're aware that no matter how high you set the number of backups to be, the DOS version of scanreg will still only display five of them. Very silly!
Anyway, I tried restoring the backups of system.dat and user.dat that Den had me make.
Unfortunately they wouldn't work, on boot up I got a screen saying that registry corruption had been detected and telling me to run scanreg. If I ignored that, after a series of BSODs the system loading never completed.
So, I did run scanreg as Bill told me to, and of course it just restored a backup, presumably the last one that started successfully.
Once the system was up and running again, I exported the Enum registry key to a backup, deleted it, and restarted.
I then went through all the automatic and manual device installation procedures, which took ages of course, but I've now got everything installed again apart from a few peripherals that I seldom use. I'll deal with them later!
The only thing still not working is the sound, so I've got to sort that, but it can wait too.
So, I put my pen drive in the slot (I'm using that for all the tests now as it's the simplest device, if that works I'm sure the card readers will too.)
I was very disappointed to find that nothing had changed!
It's doing exactly the same as it was before I reinstalled all the devices.
I put the drive in the USB slot, it says it's found a "Mass Storage Device".
That installs correctly, all well and good.
It then says it's found a "Removable USB Disk", then a "USB Disk".
It then does this again a second time, as my pen drive is partitioned into two drives.
Unfortunately, as soon as "USB Disk" comes up the second time, the system freezes.
No error messages or anything.
Sometimes the hourglass keeps going round and round, but the keyboard is immediately completely dead.
The mouse carries on working for a short while, although clicking on things does nothing, and eventually that freezes too. It's as if the whole operating system has just stopped running, and I have to do a hard reset.
After this, putting the pen drive in just freezes the system immediately.
If I try and boot with the pen drive in, the GUI never loads, it just hangs on a flashing cursor.
So, all that uninstalling and reinstalling seems to have done nothing.
The driver being used seems to be USBMPHLP.PDR, in the System\IOSubsys folder.
If I disable this by renaming the file (I usually disable files be replacing the middle character in the file extension with a tilda (~) BTW) the detection and loading procedure for the pen drive does complete.
I then have two USB Drives in Device Manager, as I would expect, but non functional with yellow marks on them of course as the driver file is missing.
If I reactivate USBMPHLP.PDR the system freezes agian as soon as I put the pen drive into the USB port.
So, it seems that the loading, or attempting to load, USBMPHLP.PDR is freezing the system.
Why? Well, over to you two again.
This post has been edited by Dave-H: 25 October 2009 - 07:31 AM