This was a Compaq Presario SR1750NX with Athlon 64 3500+ 2.2 GHz when I bought it in 2005.
In 2007, I put in an AMD A64 X2 4200+
In 2011, I replaced the mobo with the Biostar A880G+ paired with an Athlon II X2 270 and 4 GB of RAM
In 2015, when I upgraded to Windows 10, the on-board video drivers were no longer supported so I had to throw in a video card: the Radeon HD6450. I also doubled the RAM.
Now, in 2017, it's still kicking, but can't transcode Plex worth a damn, so it's getting love one more time! Migrated the OS to an SSD, and found a used AMD Phenom II X6 1045T cpu.
Also, I decided to use a Shield TV as my front end for my entertainment center, which led to me get a GeForce GTX 1050 Ti to allow for Gamestream, since apparently this old dog can be taught some new tricks.
Cut to later in 2017: my motherboard died. So I rebuilt everything with a new ASRock 970M PRO3 motherboard. Very happy with this because I finally have USB 3.0 ports and things generally work better.
Gamestream is awesome. I'm running Fallout 4 with medium/high settings and it works great. I also do a lot of Overwatch and I'm trying out BF1, which should push the limits.