Thank you for the reply Zorginho.
I first flashed the latest ROM You mentioned. But the result is same. Phone hangs at the boot screen (with a huge android logo filling the whole screen)
Then i tried to flash the latest .bin file usind Acer Tool (still without boot, but Acer Tool reports that the phone is connected), but the Acer Tool just crashes. I've tried Acer Tool 3.1 and 3.7. Both of them crash.
Thank you for your time and replies.