This computer started as a refurbished HP z400 workstation that I purchased for $410 (Pictures 1,2). It came with 2 hard drives, one that has since migrated to my other pc. The best part is that through curious circumstances the computer came with four Windows 7 Pro licenses. One preinstalled on each hard drive, and two stickers on the case. All of the licenses were different.
After a few months of use the innards of the computer migrated to Fractal Design arc midi r2 case (picture 3). Later that year I purchased a Nvidia GTX 960, a new monitor, and a corsair cx600m power supply to serve the new GPU and its two 6 pin PCIE power cable requirement. The proprietary power supply stayed in the case to keep the motherboard happy (it would only boot when connected to the 24 pin ATX connector of the proprietary power supply) and the cx600 was taped to the top of the case. I later upgraded the CPU cooler to a Cooler Master Hyper 212 EVO unit, and added a Samsung SSD. Over Christmas I build a custom chassis and the motherboard and other components migrated yet again (picture 4, next to the Fractal case).
Recently I purchased a new motherboard and processor to build a new system with, (pcpartpicker.com/b/dhf8TW) so the Quadro moved back in and the GTX 960 moved out, taking the cx600 with it (pictures 5,6,7 in front of my current computer). I eventually overclocked the GTX 960 to 1590 MHz stable, unfortunately the Xeon is not unlocked, so no overclock there. Everything has worked really well, it is a very powerful computer, just a bit of a pain to use without USB 3.0, SATA 3.0 and some other modern features.
And yes, some components have wandered between pictures, I couldn't find pictures of each stage exactly as it was.