My first computer was a Sinclair ZX81 bought for me by my Grandfather. I still have it, and I suspect it probably would still work too.
At university in 1988 I bought my first PC...
12MHz 286 processor
1MB RAM
5.25" floppy drive
3.5" floppy drive
And for the time a very good graphics card, that could do up 800x600 pixels in 16 colours!
All the above was brand new.
Attached to it was a second hand colour monitor I bought at an auction for about £140. It was 12", and colour monitors were quite rare. This one turned out to be multi-sync, which was even rarer, and the price had I bought a new one would have been £1000!!!
In 1991 I upgraded it by installing a hard drive. It was an RLL drive. the whole thing is 5.25" wide and fills TWO standard drive bays familiar on most PCs nowadays. It had a dedicated ISA card that connected it to the computer.
The monitor I got rid of years ago, even at 12" it was just too bulky. The computer still sits under my bed.
Guess what? It still works, and boots to MS-DOS 5 in about 15 seconds. Windows? What's that!?