By far, the most common cause of hardware problems is using hardware that is not listed on the Hardware Compatibility List (HCL), which lists the supported hardware components that have been tested and have passed compatibility testing with Windows NT version 3.5 as of October, 1994. A copy of the most current HCL is included in Appendix D, "Hardware Compatibility List." It is especially important for you to refer to the HCL if you plan to use any of the following hardware components: modems, tape backup units, and SCSI adapters.
Make sure that you are using a make and model that is listed on the HCL. If several models from one manufacture are included in the HCL, only those models are supported; a slightly different model might cause problems. Where special criteria are required for a model to be supported (for example, if a particular version of driver is required) this is noted as a footnote in the HCL. Be sure that your configuration meets these criteria. As additional hardware is tested, the HCL is updated, and additional drivers are created if needed. The updated list and additional drivers are available through the electronic services listed at the end of the HCL.
If you are sure your particular hardware is supported, and you are still having problems, always begin by checking that the physical connections are secure. This simple step is easy to overlook when you are thinking in terms of compatibility issues, resource conflicts, and configuration parameters.
If you are using a SCSI device, double and triple-check the SCSI termination. Even if you are sure the termination is correct, if you are having problems that could be due to incorrect termination, open the computer case and check again.
Next, check your hardware configuration. Windows NT is more exacting than most other operating systems. So I/O conflicts and interrupt conflicts that went unnoticed under another operating system must be resolved when you switch to Windows NT. Likewise, you must pay much closer attention to CMOS and EISA configuration parameters when using Windows NT.
If you encounter video problems, such as an incorrect display or very slow screen updates, you can usually determine whether the problem is with the video component or with some other component by switching from super VGA to plain VGA. For example, restart the computer, and choose plain VGA during the boot sequence. If the problem goes away, look to the video component for the source of the problem.