Are you the kind of person who has to know everything that's going on in your system, and I mean absolutely everything? Then the free LookInMyPC is for you. It reports on the state of your system in exceptionally fine detail. Sure, it has the usuals, such as manufacturer, serial number, amount of RAM, hard disk space, and so on. But that's just a start. Want to know the part number of your RAM chips? It'll tell you that. How about all of your installed printer drivers, the name and address of your ISP, all of your installed updates and patches, your installed services....well, you get the idea. LookInMyPC does what it says--it looks in your PC in what seems like microscopic detail and then reports on the results in a local page in your default browser.
Install the program, click Generate Report, and LookInMyPC goes about its work. Be aware that the program needs a bit of time to do its analysis. In fact, you may think that it's no longer working, because after an initial notice that it's doing its job, you get no feedback and nothing seems to be happening. But be patient; after a few minutes, the report will appear in your browser. If you'd like, you can also have a report e-mailed--handy if you'd prefer to start LookInMyPC and then leave for a while.
If you want to spend less time and get a less-than-comprehensive report, that's an option, too. Before you click the Generate Report button, uncheck boxes for information you don't want, such as battery information (largely irrelevant for a desktop), or keyboard information (which is usually pretty obvious).
Especially useful is that after you generate the first report, LookInMyPC will also show you what changes have been made to your system. That report is used as a baseline, and for subsequent scans, you can see what's been changed.
It's also handy that you can install LookInMyPC as a portable installation, directly on a USB flash drive, memory card, or other removable media. You can then carry it around with you, plug it into any PC, and use it without making any changes at all to the system.
Any techie who wants to know everything going on in their system in great detail will get a lot out of LookInMyPC. For others, it may be overkill...but it's free, configurable, and so simple to use, it might be worth it, anyway.