I have seen it said that many USB devices need their drivers installed before attaching the device.
Do you have install CD's with these devices? (MP4 player, Flash Drive, USB Printer).
If so, try that, (one CD, one device at a time), and see if Windows remembers when the device is unattached, then re-attached.
Also, it is unwise simply to unattach USB devices. It is recommended that the ''Safely remove hardware'' icon in the System Tray, (where the clock is), is used to tell you when they can be unattached.
I hope this helps.
The computer I am working with is a Dell P4 desktop with 512 MB RAM, and Windows XP Home with SP2 that was purchased new in August 2005.
The problem is that every time I plug a device into the system (MP4 player, USB printer, flash drive) it is not detected. If I look in Device Manager it shows up as an unknown device. If I then try to manually install the driver, it will install properly.
I then decided to remove all USB Host Controllers, USB Root Hubs etc. After doing this and rebooting, all of these devices were unknown devices as well. Simply telling Windows to update the driver added the devices properly.
Can anyone tell me if you have seen this before and if so, what the solution is?