Can i keep my pc layed down? when off

yes

can even lay it down when its on

^ you dont want to risk your pc by accidentally doing something stupid  

power off and do the way it should be done

i wouldnt recommand laying it on its side. u can but not recommanded. unless ur case comes sitting down horizontally instead of virtically.

Laying a tower case on its side for maintenance, such as installing the motherboard or a video card, is normal, and you want the computer off first for that. Make sure any optical media is removed first. Powering it on while it's still horizontal is risky, unless (as iceclock mentioned) your case is designed to be horizontal.

it wont hurt but more than likely something will get spilled and go everywhere inside your case depending on the cooling etc

its not designed to be flat, also u might fall on it or knock into it  

i find its much easier to install graphics cards, memory etc if its laying down and those pesky little front

panel connectors for power , reset etc

i should have said can even lay it on its side when its on--but turn it off first then lay it down before

turning it back on--and not with the heatsink hanging downwards



reasons for turning it on laying it on its side

cant fit under the desk standing up  

trouble shooting--ie remove one memory module power back up--need to remove another memory module and so forth checking all fans are spinning properly etc

obviously if its powered up use common sense

no drinks, pets , children etc

yes i agree. but i meant when its running not to be on its side.

It can be on it's side wither it's running or not. The only problem you might run into is if your optical drives be horizontal or not.

As far as hardware as long as it's not upside down (then I could see a problem due to weight) it's not gonna hurt anything as long as you're still getting decent airflow.

why not?

any practical reason?--you can fall on it or knock into it or spill something on it just the same if its standing up

runs fine on its side

unless you have a water cooling set up then maybe not a good idea

Just make sure the switch on the power supply is off too. There is power supplied to the board by the psu unless it is off or unplugged.

no hello, certain cases are made to run vertical and some horizontal, u guys are way off.

only when installing things and its off be on the side. not meant for operations on the side when case is made vertical.

Do a google search you will see it's not a big deal provided you arn't hurting the airflow to much and heat is still able to be easily pushed out. Obviously make sure you mobo is facing up and not down like I said before. And like I said before the optical drive may or may not end up having issues.

Also I would not advice sitting anything on top of it as the side panel isn't made to take weight like a top panel might me for a horizontal case.

that means do not sit on ur case while eating cheerios