I have had my 360 for about 4 years now. I hadn't touched my 360 in about 4 months (because of the wiiU) but I recently decided to order tales of vesperia from Amazon. So I tried to go on my xbox360, but my controller wouldn't connect. The weird thing is that it can open my 360 when I push on the middle button but it then just keeps blinking forever. I tried syncing it which didn't work. I tried changing batteries which also didn't work. 

I doubt my controller is broken because it is capable of opening my 360, it just won't connect to it (which is kinda weird considering it is capable of opening the 360).

Anyways, can anyone help me please?

Did you try holding down the wave line button on the consoles and the controller?

As I said in the OP, I already tried syncing my controller to the 360 =/.

Hmm maybe someone else can help or maybe a quick google search would benefit you more than creating a thread about it. 

I did google search... And the only things that I found was "change the batteries" or "sync your controller". Trust me, I wouldn't waste my time creating this thread if the answer was on google...

I don't know if it is the same for Micro's controller, but the PS3 one has a little hole with a little button you can access with a needle that once pressed resets the controller. Maybe Micro's controller has it as well.

I don't see any other info on what the problem could be so maybe you will have to just buy a new controller. Sorry I couldn't be more helpful. 

on the ps3 controller i was told there is a very small restart button at the back, if there anything like that with the 360?

Nothing like that on the 360 controller. 

happened to one of mine. Never managed to fix it:/