I'm experiencing an annoying problem with my USB controller. Short story: My USB won't work when I have network, audiocard and Nvidia installed simultaneuosly. My system: ASUS a7v333-x motherboard ACPI BIOS rev 1004 AMD Athlon(TM) XP 1700+ Nvidia Geforce MX 420 ASUSTek/Broadcom 440x 10/100 Integrated controller Realtek AC'97 Audio for VIA (R) Audio controller IRQ 0 System timer OK IRQ 1 Standard 101/102-Key or Microsoft Natural PS/2 Keyboard OK IRQ 6 Standard floppy disk controller OK IRQ 8 System CMOS/real time clock OK IRQ 9 Microsoft ACPI-Compliant System OK IRQ 12 PS/2 Compatible Mouse OK IRQ 13 Numeric data processor OK IRQ 14 Primary IDE Channel OK IRQ 15 Secondary IDE Channel OK IRQ 16 NVIDIA GeForce4 MX 420 (Microsoft Corporation) OK IRQ 18 ASUSTeK/Broadcom 440x 10/100 Integrated Controller OK IRQ 21 VIA Rev 5 or later USB Universal Host Controller OK IRQ 21 VIA Rev 5 or later USB Universal Host Controller OK IRQ 21 VIA Rev 5 or later USB Universal Host Controller OK IRQ 21 VIA USB Enhanced Host Controller OK IRQ 22 Realtek AC'97 Audio for VIA (R) Audio Controller OK Here's what I did to try to fix the problem: Upgraded BIOS and did some tweaking according to http://www.usbman.com/Troubleshooter%20General.htm#BIOS Reinstalled winXP w/SP2 integrated and my USB devices works fine. But when network, Nvidia and Audiocard is installed the USB device drivers disappear from device manager, and I'm not able to reinstall. I've rolled back to fresh XPSP2 install and tried to install the network etc. drivers in different orders, but to no avail. When all 3 are installed - no USB. I then tried to install them with drivers from asus, windows update, nvidia, gainward etc, but got the same result. When I disable one of the drivers and reboot my USB is working again. Also tried the VIA USB2.0 260-L drivers from viaarena.com Can I rule out an IRQ conflict? Is that even possible in XP? Is the VT6206 USB2.0 chip acting up? I've been at this for one week now, and I'm about to give up. Any suggestions?

I really don't know, but it sounds like it could be some kind of power problem--there's just not enough power available for all four devices simultaneously. One or more of these devices was added after your PC purchase? Try to check the power specs of your PC and devices. Good luck. Terry

It's not a power problem. I finally got it working, but I had to install win2000, so I'm running dual xp/2000 now. Have no idea why it won't work on xp though.