Resolving Hardware Conflicts

Resolving conflicts

There are four rules you should always follow when making system changes.

1. Ask questions first - Shoot later!
   It seems obvious but there are probably other people who have had the same problem with the hardware you are installing.
   Try visiting the manufacturers website first or post a message in a relevant newsgroup - Visit the Techrescue.net datasheets available on the front page for a list of all the manufacturers websites and also the specialist newsgroups by hardware type.
   I know, I know, who wants to wait for a reply before using their new hardware, although you will be amazed how quickly you can get an answer through a specialist newsgroup which can save you hours of frustration, effort and swearing to sledgehammer your new device into your system!
2. ONLY MAKE ONE CONFIGURATION CHANGE AT A TIME!
   Make sure you only make one change before you re-boot, otherwise you will have no idea which change has been the correct one. You can get yourself in an awful mess if you start to change multiple settings.
3. Write down everything! Including changes you make in the order that you made them!
   Before you make any changes to your system it is advisable to write down the current settings for the BIOS and the operating system. You can then restore everything to the original settings should anything go wrong.
   Writing every change down in the order you made them will ensure that you can back-out any changes you have made which are causing more problems than they solve. 
4. Give yourself a chance!
   It is always a good idea to try and free up as many unused resources in the system as possible, BEFORE you start trying to resolve a conflict.
   You should be able to disable allocation of resources such as IRQ's to COM ports, USB ports and Printer ports(LPT) in the BIOS if you do not use them. See the 'To BIOS or not to BIOS' section earlier in this article for more information.
   If you do this before trying to resolve a conflict you will have more free resources to try when moving the devices around.
   

Things to try

In no particular order here is a list of things to try when you experience a hardware conflict. 

Be aware that when you swap device A for device C because it was conflicting with device B.
Device C may also conflict with device B and device A may conflict with another device in the system.
See what we are up against here? 

1. Run a virus check on your system. It is not uncommon for some virus programs to cause hardware conflict symptoms.
2. Use the System Device Manager to change the resource settings for the devices that are having problems. This may not always be possible depending on Windows being set to control PNP through the System Device Manager. See 'Understanding how resources are allocated' earlier in this article for more information about changing these settings.
3. Are you installing a new graphics card in the AGP slot? Normally the first PCI slot on the motherboard shares resources with PCI slot 1 and you cannot override this. Try removing the device attached to PCI slot 1 and then re-install your AGP graphics card. If you can move the device that was attached to PCI slot 1 then all the better. Graphics cards are notoriously bad at sharing resources, especially when they are being taxed heavily.
4. Completely remove old drivers if you are replacing a device with a new one. This can be particularly important if you are changing graphics cards. It is always a good idea to boot into safe mode and use the 'Add/Remove Programs' in Control Panel to uninstall the old drivers for a device which is no longer in use. In some cases you may have to edit the registry to completely remove old drivers.
5. Change jumper settings on new hardware to re-configure it. Remove and reinstall device to see if this will make a difference.
6. Remove other devices and add new device before re-adding existing devices. This can be tricky and time consuming because you may have to uninstall drivers for the old device before installing the new device with it's own drivers.
7. Is the device you are installing, similar to another in the system? Sometimes a device can use resources that are normally reserved for the system. COM ports have always been a culprit when adding a new modem for instance. COM ports 1 & 3 normally share resources as do COM port 2 & 4. If you add a modem which is automatically set to use COM 1 and you have a serial mouse attached to COM 1 then you can almost guarantee a conflict.
8. Swap devices around on the motherboard. If device A and B are conflicting then change device A with device C. Again this can be time consuming because you may have to uninstall/re-install drivers.
9. Remove existing devices and replace with the new device one at a time until the conflict disappears. Re-add the existing cards in the reverse order, given that the last device you removed seemed to clear the conflict i.e.
   Devices A, B & C exist in the system. You have installed device D which has a conflict.
   Remove device A and replace with device D.
   If conflict remains then remove device B and replace with device D.
   If conflict remains then remove device C and replace with device D.
   If conflict clears then re-install device A, followed by device B, followed by device C.
   If the conflict returns when re-installing you may have to move the devices around until you find the combination of slots and devices and resources that suits.
10. If all else fails then you may have to resign yourself to the fact that the only way you will be able to resolve the conflict is to remove a device that you don't use and do without. Alternatively you could try exchanging it for a different model which will hopefully have different resource requirements.
11. Upgrading your operating system MIGHT help. I stress might because later versions of operating systems, especially Windows, handle resources much better than their previous versions. Windows 95 Introduced the Plug and Play concept and is now pretty much out of date. Windows 98SE handles IRQ sharing much better than Windows 98. Windows 2000 and Windows XP handle resource allocation completely differently from previous Windows versions and probably have the best chance of getting your combination of hardware to work. Note that XP may require a certified Windows driver to install a device. If you have old devices in your system it is worth checking that new XP drivers are available before upgrading, otherwise you may have to pay for a new device as well as an operating system!

The last resort!

You can rest assured that somebody, somewhere will tell you that the only way to get your hardware to work properly is to re-install your operating system.

I have only ever resorted to this drastic measure a few times. Once because I took someone's advice to do so and at other times because I managed to get my system in such a mess trying to resolve a conflict that I had no option but to re-install the operating system.

ON ALL OF THE OCCASIONS I HAVE RE-INSTALLED AN OPERATING SYSTEM TO CLEAR A CONFLICT, THE CONFLICT HAS RETURNED!

It's up to you if you want to take the chance but I wouldn't recommend it.

GOOD LUCK!

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