I start my herm200 only htc logo comes to screen,

..switch on and try hardreset :

Press and hold the Left SOFT KEY and Right SOFT KEY, and at the same time, use the stylus to press the RESET button at the bottom of your device. You will be presented with a menu saying 'press R to reset, X to exit', if you press R Your device will be set back to factory default settings.
(The L/R soft keys are the "- -" keys just above the start and OK buttons)

here also with some pictures:
http://www.hardreset.eu/htc_tytn_hermes_hard_reset_soft_reset_en.html

if your hard reset hasn't worked, flash a replacement rom on to it.

step by step guide here
http://tiltmobility.com/how-to-flash-your-device/

plz contact my number 00919900226027