dead arduino?

I just decided to make some projects for my arduino uno, so I took it out after like half an year, but when I plug it in the PC both LEDs (orange & green) blink 3-4 times, Windows plays the "connected" sound, then disconnected one and says that there might be something wrong with my device, leds then either stop completely or blink/shine randomly, like, they can blink really fast and then just shine with 10% brightness, blink again and all sorts of random stuff...

should I get a new one or?

Is the cable good? Otherwise the 16u2 USB-serial chip is dead.

What windows version?

A lot can have changed in half a year.

Did you install any (not necessarily Arduino related) software? Two people (I'm one of them) have reported an issue with the Huawei HiSuite killing the communication.

Is your Uno a clone (with FTDI chip) or an original? If a clone, maybe a fake FTDI chip and Windows update 'killed' the communication (not sure which windows version this applies to, but it seems to be a known issue).

@Isaac96

I'm not sure whether the cable is good, how should I check it ?

@rpt007

10

@sterretje

I didn't really install any software that could interfere with the communication, at least I'm not aware of it and I also have no idea whether the Uno is a clone or an original, basically my friend bought one for me when he was ordering one for himself so we save shipping, but I have no idea where from he got it, so... if I'm not mistaken the box looked like this http://store.amberspyglass.co.uk/images/source/Electronics/arduino-uno-box-2.jpg or something similar

Try another cable.
Does it have a gold polyfuse next to the USB port? Clones and counterfeits have a green one generally.