that says it all. Since the problem started after this, you've answered your own question.
Either the mobo specs & drivers are incorrect or need updating (chipset/bios or you got a defective unit.
Another thing to think about, what caused the mobo failure?
I recently had a new Asus K8V-MX Motherboard fitted to my three year-old Mesh Matrix computer, since which time, no portable devices are seen in My Computer. They are picked up and correctly identified on the systray, but each time I want to use any flash drive or portable device I have to assign it a drive letter through Windows XP (Home Edition) Disk Management.
Even then it is only visible in Windows Explorer where I can actually see and access my files. No portable device ever shows up in My Computer.
If I unplug the device and plug it in again, without having rebooted, although the letter still appears in the list of drives, I have to add a new letter to the same device in order to be able to see the files on it once more. If I reboot, the drive vanishes, and I have to start over again.
Is it perhaps something strange in the Registry that may be causing this?
All devices work, the USB port settings are fine, but it cannot automatically be seen.
I have tried reloading the chipset from the motherboard CD and have also added the Registry tweak so that all unused USB devices can be seen, have then uninstalled then allowed them to reinstall themselves.