USB 2.0 keeps reverting to USB 1

I have a computer desktop thats now a few years old. It has onboard an
Intel 82801BA/BAM USB 1 controler. Because I wanted to upgrade to hi
speed, it purchased a PCI USB 2.0 controller, which the system reports
as a VIA Rev 5 or later. From the very start XP refused to recognise it
as USB 2, and I was getting the stupid message "your device can perform
faster" etc, everyting time I pluged ANY USB2 device. I did manage to
find some VIA specific drivers on the internet that appeared to fix the
problem, but only as long as I did not switch the computer off (standard
reboot does not effect it). When I perform a cold boot the VIA USB2
Enhanced Host Controler has vanished, and again I get the daft "your
device can perform faster". I now have the problem of having to
reinstall the drivers evertime I want to use my webcam, memory stick,
etc. This is driving me crazy, and obviously is not what should be
happening. Strangly, if I view hidden devices in device manager, it
still exists, but greyed out. Note that I only plug USB1 devices
(keyboard, mouse etc) into the onboard intel USB 1 ports.
Please note that the system BIOS is running latest version.


My system is as follows

Windows XP Professional Service Pack 3 (build 2600)
Install Language: English (United States)
System Locale: English (United Kingdom)
Installed: 10/12/2008 12:21:27
1.60 gigahertz Intel Pentium 4
8 kilobyte primary memory cache
256 kilobyte secondary memory cache
Not hyper-threaded
Viglen W2KSEL 00:03:47:E5:73:40
System Serial Number: 1550451
Board: Intel Corporation D850MV AAA56423-301
Serial Number: IUMV20712429
Bus Clock: 100 megahertz
BIOS: Intel Corp. MV85010A.86A.0067.P24.0304081124 04/08/2003


Any ideas on my problem would be very appreciated.

Thanks