Win XP Home SP.3

In the past week my system has CRASHED three times with exactly the same bsod. Details extracted from the minidump by BlueScreenView are shown below.

Any guidance as to a fix please?

TIA

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Dump File : Mini091011-01.dmp
Crash Time : Sat 10/09/2011 20:06:33
Bug Check String : DRIVER_IRQL_NOT_LESS_OR_EQUAL
Bug Check Code : 0x100000d1
Parameter 1 : 0x00003316
Parameter 2 : 0x00000002
Parameter 3 : 0x00000000
Parameter 4 : 0xf71fc507
Caused By Driver : USBPORT.SYS
Caused By Address : USBPORT.SYS+6507
File Description : USB 1.1 & 2.0 Port Driver
Product Name : Microsoft® Windows® Operating System
Company : Microsoft Corporation
File Version : 5.1.2600.5512 (xpsp.080413-2108)
PROCESSOR : 32-bit
Crash Address : USBPORT.SYS+6507
Stack Address 1 : USBPORT.SYS+c362
Stack Address 2 : USBPORT.SYS+d3c6
Stack Address 3 : USBPORT.SYS+14350
Computer Name :
FULL Path : C:\WINDOWS\Minidump\Mini091011-01.dmp
Processors Count : 1
Major Version : 15
Minor Version : 2600
Dump File Size : 90,112
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That error is typically caused by bad or conflicting drivers. Have you recently updated any drivers?

1) Look in device manager - any errors?
2) Check for an updated chipset driver
3) Check for a bios update

Let's go from there.Thank you Allan.

No driver updates installed for many months and then only for a generic modem. I've tried uninstalling that driver but because the system CRASHES spasmodically cannot be sure that driver was the cause. If no crash for another week I'll reinstall the driver and go from there. No crash for 5 days.

1. No device manager errors.

2. Chipset driver update found but the Intel Driver Update Utility carries this warning The Intel Chipset Software Installation Utility provides functionality for AGP and USB, not drivers for AGP or USB. DO NOT DOWNLOAD THIS UTILITY IF YOUR DEVICE MANUFACTURER IS RECOMMENDING IT TO CORRECT AN "AGP DRIVER," "AGP GART," OR "USB DRIVER" ISSUE; IT WILL NOT CORRECT YOUR ISSUE.

3. Bios update not found..

Try disabling onboard USB controllers on your BIOS settings(if available). Does it still bluescreens? You could ALSO use SystemFile Checker to check for any errors. http://www.bleepingcomputer.com/forums/topic43051.htmlDoes the blue screen error randomly or when you are performing a specific function (or when a usb device is connected)?Bsods occur randomly whether or not there is a usb device connected, but no bsod now for nine days. I will reinstall the modem driver shortly and see what happens.

Thanks.