I'm really sorry.I was a bit busy (sorry for my english too).Thank you very much for responding and i'm really thanksful for your help.
Yes,i tried to reset it from settings and reset phone,nope,the gear and the process bar appear for only a few second (the progress bar don't move at all),after that the phone restart without it been reset.
I also try the button combination:
Press and hold the VOLUME DOWN button
Tap the POWER button while still holding the VOLUME DOWN button
When an icon appears on the screen, release the VOLUME DOWN button
Press the following buttons in this exact sequence:
VOLUME UP > VOLUME DOWN > POWER > VOLUME DOWN.
same issue:the gear and the process bar appear for only a few second,after that the phone restart without it been reset.
I tried so many time,pressing the button with various delay,sometimes with the camera button,while the htc logo appears,etc..
I also tried it with/without the simcard,with the charger plugged,with a full/very low battery.I was about to flash it with a stock rom but i was affraid that will brick the phone.
I got those problem when i update to 8.0.10532.166 to get the wp8.1 preview,unforunfortunately the downloading of wp 8.1 stuck at 67%,the memory of my phone get full (325 mo left),it says that i should free memory space to download it but i already delete all my applications and games.the only way i could do it was to reset my phone,but it won't.So i 'm here unable to update my phone,to reset it,even to install any application.
Sorry for my long post,and for my english (again).I make my best to avoid any fault.