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>Is there a way to write codes to detect the availability of the hardwares on a pc? such as bios, motherboard, video card ... etc.
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Yes. You can use the WMI (Windows Management Instruments) API to query almost any information that you could ever want. For more information on it start with the MSDN - Platform SDK - Management Services - Windows Management Instruments. You can look through the WMI Reference - WMI Classes - Win32 Classes to get an idea of the kinds of information that is available.

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>How would I write codes to determine what software is installed on the hard drive?
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Some of this can be achieved with the WMI also. However, most of what you will get returned to you with it will be Microsoft products. Only a few others have taken the time to log their software as being installed here. Other than that you might search for information regarding the registry and what keys hold the information for the Add/Remove Programs part of the Control Panel.

Good Luck,

REM