One of the extremely fun 'retro-tech' custom LEGO sets by Chris McVeigh -- https://chrismcveigh.com/ His story is amusing and inspiring: a huge AFOL, Chris had been publishing his own neat and well-designed sets (incl. custom decals and stickers) for about eight years, until in 2019 he finally went on to join LEGO officially, as the designer in Creator Expert/Architecture team.

An Access Panel reveals the internal components of the PC: an accurate, detailed replica of the motherboard, complete with CPU, and even expansion cards that can be removed and replaced. Very nice details on the 5" floppy drive slot, a little LED light on the monitor, etc. I grouped all the elements so you can disassemble the System Unit and Monitor easily.

Instructions: https://chrismcveigh.com/lego_kit_guides_2018/my_first_computer_pc.pdf

This is an exact build, following the original manual with only one minor variation: Flat Tile 1x2 (med. stone grey) with custom 'CPU chip' sticker >>> Replaced with #3069d250 'Flat Tile 1x2 No. 235' as an alternative sticker

I first found out about McVeigh's sets on LGR's YouTube channel. I highly recommend them, it's extremely fun to build, they are designed with the same attention to detail and engineering finesse than some of the best official LEGO sets, the manual is perfect and easy-to-follow, with a full inventory of pieces and all colors.