Takeaway: Brien Posey explains how to use Windows to troubleshoot hardware conflicts when you build a new computer or upgrade an old computer.When you’re trying to build a new computer or upgrade an old computer, it’s not uncommon to run into problems caused by hardware conflicts. Fortunately, you can use several tools built into Windows to troubleshoot the problems. In this article, we’ll explain how to use Windows to troubleshoot hardware conflicts.
Before you begin
Before you begin to delve deeply into Windows, you should check your system for an easily resolvable conflict. To do so, boot the machine and go into the CMOS setup. The method of doing this varies between manufacturers, but it usually involves pressing [F2] or [Delete] just before the operating system begins to load.
Once you’ve entered the CMOS setup, look for a setting marked Plug And Play OS. This setting may not exist on some older systems, but it’s on almost every new PC that comes off of the assembly line. Once you locate this setting, set it to Off. Now, save your changes and reboot your system.Having the Plug And Play OS option set to On can cause certain hardware devices to attempt to use the same resources. This is especially true when using MS-DOS-based or poorly written Windows-based drivers.
At this point, Windows still might not boot correctly. You may have to let Windows redetect the devices in question. To do so, boot Windows into Safe Mode. When Windows loads, open Control Panel and double-click the System icon. When you see the System Properties sheet, select the Device Manager tab. Go through the hardware list and delete any references to hardware in your system. This list only includes add-on hardware such as video cards or network cards.
Now, reboot the computer and allow Windows to redetect the hardware. You’ll be asked to supply the appropriate driver disk for each component. When you’re done, all of the hardware should work together.
When the hardware still doesn’t work
It’s possible—especially on older systems—that the hardware still won’t work together. In such cases, it’s necessary to find and resolve the conflicts manually.To do so, return to the Device Manager. Now, double-click Computer. Doing this displays a list of resources, such as IRQs and DMAs. Browse through the lists and look for overlapping numbers. Some overlaps are OK. For example, it’s normal to see an IRQ Holder for PCI steering for each IRQ above 9. However, hardware devices shouldn’t share numbers. For example, a network card and a modem shouldn’t both share IRQ 3.
If you do find a conflict, simply locate the offending device in the Device Manager tree. When you find the device, double-click it and select the device’s Resources tab. You can then turn off the device’s automatic configuration option and manually set the device to use unused settings.
Brien M. Posey is an MCSE and works as a freelance technical writer and a network engineer for the Department of Defense. If you’d like to contact Brien, send him an e-mail . (Because of the large volume of e-mail he receives, it's impossible for him to respond to every message. However, he does read them all.)The authors and editors have taken care in preparation of the content contained herein, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.