The best way to reduce noise is to work with no hard Drive and with a ULV processor.
The datas can be in another place in the Lan.

Which PC and OS do you suggest me .



NjB

You don't need no stinkin LAN. You don't need no stinkin OS or other software.

All you need is a long VGA cord for the screen
and a long USB for the the mouse and keyboard.

You can put the printer on wireless. Maybe you can try the same for the keyboard and mouse.

USB has distance problems. Probably it is best to do this with a USB 3 card. You have to experiment but I would think you could go a fair distance with a USB 3 card driving the link.

Crude and Simple

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Newegg
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Newegg sells a 36 foot long Triplite brand USB cord for $40. Looks like it has some kind of repeater in it.
http://www.newegg.com/Product/Product.a ... 6812120627

Here is a comment from one happy user:

The longest USB I've Ever Seen

Pros: I needed to snake around my living room to cleanly get my USB keyboard and mouse connected (via a hub) to my PC across this room. This cable did the trick, and saved me lots of headache.

Cons: The midpoint of the cable has a electronic part which is a little bulky. About the size of a champagne cork.

Other Thoughts: Odd that this seems to be the only vendor selling this. I had tried USB-to-cat5 solutions and they weren't reliable in the end.

SSD for OS is the best option. it is no noise, and very low power consumption.

Most penryn Core2 CPU's on a decent motherboard with voltage options in its bios are capable of undervolting to impressive levels. 1.00v at around the 2ghz range are cakewalk with some going substantially better.

Win7 has good power management options, but its whatever you want to use.