Default What is wrong with my AT&T Galaxy s3 phone?

Hello,

A week ago I was watching the world cup on my s3, fell asleep, and woke up to a dead phone. Battery had around 70% left on it so I don't think its the battery. Tried every button combination to revive it with no luck. The phone is dead, isn't recognized by the computer, and I tried a different battery and still no luck.

When I plug it to my computer, a couple of times the computer would completely shut down but the charging red LED light would appear for a minute or two (with or without battery), then disappear. This is the only sign of life I get from the phone.

The phone is at&t but a friend of mine unlocked it for me so I could use it with t mobile. That is the only thing that I have done to the phone. I think after reading this forum an entire week I might have an impression as to what might be the problem, and it may that its hard bricked- if I am right.

I've scoured the internet for solutions, and none worked. I've tried the well-known microSD solution, and nothing happened. I bought a jig USB off eBay and it didn't work on my phone or even my brothers s3.

The phone is past warranty and the only thing that I have not done is send it for a JTAG service. But before I send it in, I want to exhaust every possible solution out there and hopefully save me $50!

Any--and I mean ANY--suggestions or helpful advice are appreciated.