Here, I have a cleaned HP ProDesk 400 G1 SFF that is in great working condition listed for sale. The ProDesk 400 G1 is a powerful desktop computer designed for office, casual computing, and is even a great option for some light gaming.

It features an Intel Core i5-4570 processor with a speed of 3.2 GHz, integrated Intel HD Graphics 4600, 4 GB RAM, and 500 GB HDD storage. This desktop runs on a fully activated copy of the Windows 11 Pro operating system, and even has the 2021 version of Microsoft Office Professional installed, providing an overall very smooth, fast, secure, and user-friendly experience.

The black coloured, compact, small form factor (SFF) design of this desktop makes it space-efficient and easy to integrate into almost any workspace.

It comes with a healthy selection of connectivity options, including DVI, VGA, USB 3.0, USB 2.0, RS-232 Serial Port, USB 3.1, and more. This HP ProDesk 400 G1 SFF also features a DVD burner optical drive, a built-in speaker.

Regarding extra internal connectivity, the system has a motherboard header where you can connect a parallel port, 3 PCI-E x1 slots, 1 PCI-E x16 slot, an internal COMB port motherboard connector incase you wish to as a second serial port to the system, lastly there is also a front media header on the motherboard next to the front USB 2.0 connector.

The computer is also upgradeable to a maximum RAM capacity of 16 GB DDR3, and can even have the CPU upgraded with an Intel Core i7-4770, and even have a low profile GPU installed for even better performance although you will be limited to using a GPU that doesn't require an additional power cable and can work with just the PCI-E power. Lastly if you want to add an SSD to the system to really get the most out of the system, there is a drive caddy underneath the main HDD that is for 2.5" drives, this way you can have a faster booting system and a large storage drive. In regards to the special screws that are used to mount the drives into the bracket, I will be taping 4 extra screws to the inside of the case in the space next to the PSU.

Overall, this desktop is a cost-effective solution for just about all your computing needs, as well as providing you with a great system that is also really reliable and will last for quite a few years.