Recently, i've tried to power my arduino with a 9 volt battery. Then my arduino's digital PWM(~) ports don't give any output. And it gives error when i try to transfer project to my arduino. I think that the 9 volt battery short-circuited the data transfer head? But it powers the arduino on. But it wiped the whole projects that was in the arduino. Then it's data transfer cable didn't transfer any datas. Anybody know why? Was it the battery?
Which Arduino? How did you connect the battery? What kind of 9V battery? Do you have external hardware connected to the Arduino?
i connected + to 3.5v one
That's half an answer to 5 questions... and it took you 3 months!
Sounds like it's time to buy a new Arduino. 9V should go to Vin or the barrel jack.
You probably have a phone charger USB cable. To transfer data, you need a USB data cable.
No, the ATMEGA328 chip was fried 
That must have been a tough 8 months... on top of the original 3.