Can I Lay my desktop on its side

[Michael_Ladd]

HP EliteDesk 8200 Windows 10 Home 

[itsmyname]

@Michael_Ladd -- yes.  But, if there are air-vents in the side that will be on the "bottom", put the computer on its other side, so that the air-vents are on the "top" of the computer.

If your computer has a CD/DVD device, it is a little tricky to insert a disc, and keep it in the correct position, while you are trying to close the "tray".  Just a light touch on the media, while the tray is moving, is enough to compensate.

[Prométhée]

hi

If you have the right model then yes since designed for

otherwise, as indicated, possible but to be avoided!

HP Compaq 8200 Elite Convertible Minitower PC

• HP Compaq 8200 Elite Small Form Factor PC
• HP Compaq 8200 Elite Microtower PC
• HP Compaq 8200 Elite All-in-One PC
• HP Compaq 8200 Elite Ultra-slim PC

Maintenance and Service Guide: 8200 Elite Series Convertible Minitower, 8200 Elite Series Microtower...

Using the Small Form Factor Computer in a Tower
Orientation
The Small Form Factor computer can be used in a tower orientation. The HP logo plate on the front
bezel is adjustable for either desktop or tower orientation.
1. Prepare the computer for disassembly

[itsmyname]

@Prométhée -- otherwise, as indicated, possible but to be avoided!

I strongly disagree. 

For example, look at any All-In-One computer -- the motherboard, CD/DVD drive, and other components all work fine while "vertically" oriented. Note that there is no "up-or-down" for a SSD, since there are no moving parts.

Another example is those small-size computers that can be mounted on the back of the spine of the stand of a computer monitor.  Those computers work fine, whether "vertical" or "horizontal".

[Prométhée]

"For example, look at any All-In-One computer -- the motherboard, CD/DVD drive, and other components all work fine while "vertically" oriented. "

Bad example
since the computer was designed to be in this position!
Now I'm not saying it's impossible, just that I don't recommend it unless, as mentioned, the computer is designed for both positions.
A simple example, you don't pay attention, the switching of the computer causes a cable to fall on a fan, too bad

conclusion
check it out, and don't do it anyhow

[itsmyname]

@Prométhée -- the switching of the computer causes a cable to fall on a fan, too bad

It is unfortunate that you lower yourself to use a "strawman" argument.

It is a form of argument and an informal fallacy of having the impression of refuting an argument, whereas the real subject of the argument was not addressed or refuted, but instead replaced with a false one.

Your non-helpful response does not assist the author of the question.