My mother needed a new PC and this fits the need perfectly.  It's very clean (though you can see some evidence of how dusty it was originally in a couple places,) it comes with a genuine Windows 10 license, and I found no bloatware other than VLC player which was kind of odd to have installed.  PC also had little smell; sometimes you get one a smoker used and no matter how well you clean it, it reeks. Again this PC was very clean.  3 of the 4 DIMM slots are populated, 2G+2G+4G.  Probably a good idea to reseat the RAM given it's a used PC.  Not sure why neither the serial or product number are found on HP's support site, but you can find it using just the 'HP Compaq 8200 Elite' designation.  You won't find any Windows 10 drivers, nor should you need any.  Performance wise, it's good as a email/web surfing PC, but anything with more demanding graphics will need a dedicated video card; the Intel HD graphics are built into the CPU and it's really limited.  Passmark gives the PC overall a 1144 score; CPU 6016, 2D 599, 3D 170, memory 1605, disk 843.  It's a slim case so a video card would have to be low profile, but the slots are there.  The PC boots quickly enough, relying on the Windows 10 hybrid sleep.  A SSD would make quite a difference though.  The keyboard and mouse included are very inexpensive.. I would almost rather not get them and save the $8 it probably cost for the pair.  You'll want something better.