The Antikythera mechanism (/ˌæntɨkɨˈθɪərə/ ant-i-ki-theer-ə or /ˌæntɨˈkɪθərə/ ant-i-kith-ə-rə) is an ancient analog computer designed to predict astronomical positions and eclipses for calendrical and astrological purposes, as well as the cycles of Olympic Games.

Found housed in a 340 × 180 × 90 mm wooden box, the device is a complex clockwork mechanism composed of at least 30 meshing bronze gears. Its remains were found as 82 separate fragments, of which only seven contain any gears or significant inscriptions. The largest gear (clearly visible in Fragment A at right) is approximately 140 mm in diameter and originally had 223 teeth.

http://en.wikipedia.org/wiki/Antikythera_mechanism

Pre-MS Windows computer... you probably not get much attention in Thailand for anything that doesn't run MS Windows

The Antikythera mechanism ... is an ancient analog computer

Or it's a fake.

Or the age attributed to it is wrong by at least 15 Centuries.

My money would be on "fake".

Not a fake. Gears were encrusted with oxidation and sediment when they were found in 1900 during the first underwater archaeological excavation of a Greek shipwreck, which was datable. The instrument was then ignored until the 1940's when a scientist first tried to analyze the device using X-ray technology. So, if it was a fake no one profited from it. Further analysis using advances in imaging have enhanced the picture considerably. Inscriptions in archaic Greek on the elements of the device offer further dating evidence.

Numerous ancient writers make reference to automata in the shape of men or animals that showed complicated movements which would have required advanced knowledge of gearing. But those writers were disbelieved by historians partly because no such devices survived. But the anti-kythera device changes the picture.

Not a fake. Gears were encrusted with oxidation and sediment when they were found in 1900 during the first underwater archaeological excavation of a Greek shipwreck, which was datable. The instrument was then ignored until the 1940's when a scientist first tried to analyze the device using X-ray technology. So, if it was a fake no one profited from it. Further analysis using advances in imaging have enhanced the picture considerably. Inscriptions in archaic Greek on the elements of the device offer further dating evidence.

Numerous ancient writers make reference to automata in the shape of men or animals that showed complicated movements which would have required advanced knowledge of gearing. But those writers were disbelieved by historians partly because no such devices survived. But the anti-kythera device changes the picture.

Oxidation is easy to fake, as is sediment encrustation.

Not all fakes are motivated by profit. Consider Piltdown Man, for example, or the Cottingly Fairies.

Ancient inscriptions are easy to forge.

Given that nothing similar has been found of similar date, and comparable technology wasn't developed until a millennium and a half later than the putative date, this screams "fake" to me.

As for ancient writers referred to complicated mechanisms, the descriptions are easily misinterpreted. For example, in the Bible, we read:

"Now as I looked at the living beings, behold, there was one wheel on the earth beside the living beings, for each of the four of them. The appearance of the wheels and their workmanship was like sparkling beryl, and all four of them had the same form, their appearance and workmanship being as if one wheel were within another. Whenever they moved, they moved in any of their four directions without turning as they moved. As for their rims they were lofty and awesome, and the rims of all four of them were full of eyes round about. Whenever the living beings moved, the wheels moved with them. And whenever the living beings rose from the earth, the wheels rose also." Ezekiel 1:15-19

To me this reads as prophetic gibberish. However, others have interpreted it as proof that aliens have visited this planet.