
Found this for really cheap (and half off!) at a thrift store. It came with a lower processor, no RAM and no HD but I had extra stuff lying around anyways. It had some scuffs on it and I used a magic eraser... and accidentally erased the badge where it says "OPTIPLEX 755." Oh well.
Intel Core 2 Duo E7500 2.93GHz dual core processor
4GB DDR2 RAMATI RADEON HD2400 Pro 256MB PCIe video card
DVD-RW drive
DVD-ROM drive
3.5" floppy drive
320GB 7200RPM HDWindows XP Professional
PCI FireWire card
2xUSB 2.0 ports front
6xUSB 2.0 ports rear
Audio in/out jacks front/rear
Ethernet
Parallel port
Serial port
DMS59
S-Video

Rear

Spray painted the sides silver... close to original color. The original paint was faded and had all sorts of marks

Other side

Side panel removed

Closeup of the cards

BIOS screen

Programs + specs

Windows XP desktop which you've seen 453 times by now...

Runs quite well after the cleanup! Will just toss in a slightly better GPU at some point and it'll be set. I only got it for the floppy drive since i have no machines with one atm.
HP Z420 Workstation Intel Xeon E5-1620, 32GB, RADEON HD7850 2GB, SSD + HD, XP/7
