Robert is on the money - one of the USB device drivers that you have needs updating. Since the modem is the only device in constant use, I would start there. Note what you're up to just before the next event - it may be another device that you're using. Iomegaware was causing this on a client's PC.

Bill

: : Every few hours my computer crashes to the BSOD with the following error:

: : DRIVER_IRQL_NOT_LESS_OR_EQUAL
: : STOP: 0x00000D1 (0xB3634a80,....., 0xF8828E6F)
: : USBUHCI.SYS - ADDRESS F8828E6F BASE AT F8826000, DATESTAMP 3d6ddc30

: : The addresses differ everytime, but USBUHCI.SYS is always the listed culprit. Is USBUHCI.SYS corrupted and need to be re-installed? If so, how? Should I re-install SP-1 even though it came with my oem Windows XP disc? I am having no other problems, but it is getting annoying having to reboot have few hours. If anyone has an answer, I sure would appreciate it. If you need more info, let me know. Thanks.

: : I am running the following configuration:

: : Windows XP SP 1
: : ATHLON XP 2000+
: : MSI KT4 ULTRA MOBO
: : 512MB DDR333 RAM
: : WD 80 HD
: : LITE-ON DVD & CD-RW Drives

: : My connected USB devices are:
: : Sandisk Imagemate SDDR-09
: : IPM DATACOM Webpower ADSL modem
: : Logitech Quickcam 3000 Pro

: Most probably it is a call from another driver to USBUHCI.SYS which causes the problem.
: Try searching for newer drivers for your USB devices.
: Try unplugging each device until you get no errors anymore.

: Bill will tell you other checks.