I cant use my Arduino UNO

I was using my Arduino UNO with my old computer , then i didnt use it for about 4 months , in this time i bought a new pc and recently i tried to connect it to my new pc and when i connected the usb its LEDs turned on all 3 of them and they didnt turn off. I cant see my Arduino and i cant see it in my device manager. I dont even have a COM3 port in my device manager please help me !!

Post a link to where you got the board from.

Cant you help me here ?

Not without seeing where you bought the board from so that it can be identified. For that a link to where you bought the board from would help.

http://www.robitshop.com/Arduino-UNO-R3-Yeni-Versiyon,PR-1727.html

What version of Windows are you using?

Did you install the Uno device driver?

Cena did you install Arduino on your NEW computer? If you did, go to DEVICE MANAGER and locate the Arduino folder and install Arduino that way. I'm suprised that Arduino has got so pad. Arduino site won't work on all browsers and has many pop ups via a hacker. The instructions on how to install Arduino aren't really all that clear.