Is there any dust free PC case?

[Noki]

Is there dust free PC case to buy?
i mean something hermeticly closed, and cooled by inside wather cooling. I am sick of dust in my pc.

[Snehasis]

Since cases will have ventilation holes in them how do you expect them to be dust free?
Perhaps an air cleaner (table top, floor model, etc) could help by filtering out particulate matter. However; I was watching a T.V. program years ago that stated an air cleaner with an ionizer should never be used around computer equipment, and shouldn't even be in the same room with computer equipment.

[Geo3213]

No case is dust proof
What you can do is find a case not too big so just estimate how much room will be needed. Now look for different cases on newegg.com around the size you need. I will fix 3-7 fans in it & vaccuum it out twice a month.
This is what i can suggest you!

[Nicodemus]

Even easier $3 worth of filter foam will be enough to cover all openings if the case isn't already dust filter. A weekly vacuum will minimise dust build up and allow the filters to work efficiently, i haven't had any dust bunnies in many year now.

[Chandran12]

The Antec 900. Right now at newegg it is cheaper than it has ever been. The Antec 900 is loaded with blue glowing fans with a huge 200 millimeter top fan that sucks out the hot air. It keeps your computer cool even in the hot summer. I own one and love it. My friends say it looks like a nuclear reactor. By the way, it is also quite with the fans set on low.

[vlc]

Try a google search for 'marine pc' - they're sealed from sea-air so would also exclude dust.
Homemade solution would be to put a regular desktop in a small frost-free freezer with heat-pipes sticking out.