My (mid-tower case) PC has no side covers on it. It usually doesn’t have any covers on it because I often add/remove/swap components and it’s a pain to wrestle with the covers taking them off and putting them back on again. Plus, I lose the screws. Is this a problem? I don’t stick my finger into the computer unintentionally and I don’t drop things into it. It has a power supply fan and an CPU fan. It doesn’t need to last more than 3-5 years since it will be just so much obsolete junk by then anyway. Can anyone think of any good reason for me to put the covers back on it?
PC may cause near-by monitor screen to flicker. Covers block this radiation. Dust, in my opinion, won’t harm PC in 5 years, but who knows, there are fans blowing. Some people are said to fart dust.
Well, if you don’t have any pets I don’t see why not. It’s a cheap replacement for a broken CPU fan too 
. I run one PC with the top open most of the time and I’ve had no problems whatsoever. Just be careful not to drop anything in it and I wouldn’t smoke around it either (forms a horrible gel on computer components - sick).
It probably isn’t meeting FCC regulations on radiated RF emissions without the cover. This probably wouldn’t be a problem unless you’re trying to pick up a weak radio station.
Depending on how it was designed, you may screw up the air flow over the CPU, motherboard, harddrive, etc. Especially in a high-end PC, the entire system of fans, parts placement, etc. are designed to cool the system effectively. Taking the cover off may actually reduce air flow over certain components.
This probably isn’t an issue with a normal PC, but a big server might overheat without the cover on (and all air directors (usually shaped styrofoam blocks) and fans in place).
Arjuna34
I run my PC with the cover off. The reason is, I overclock, and I overheat if it stays on. I haven’t had the cover on it in a long time, and it still runs great. I don’t know about the covers blocking the RF emissions. They’re usually not real good covers to begin with. Also, it sits right next to my monitor and has never done anything weird to it.