HTC Saga Only turns ON if connected to PC
I have a problem with my HTC Desire S (Saga). I rooted it before, then changed ROMs then was ok. Then later on, the phone just started to turn itself on and off. Tried to install an RUU of it but don't know if it was the correct one. Then now, the phone only turns on when connected to PC. If connected to wall charger, it will just charge. And when I try to turn it on, it will just flicker, then it will try itself to turn on but didn't, then the process just go on and on. But when I connect to the PC it works fine. The phone looks normal, but has to be connected to the PC. Once I remove it, the phone shuts itself off.
HTC Desire S (Saga)
Baseband Version 20.28d.30.0805U_3805.04.02.01_M
Kernel Version 184.108.40.206-g241e3af
Please help, I really love this phone. And it already has a sentimental value for me.