my htc one sv has stopped working, can anyone help!

[wheatabix36]

hi Guys, my htc one sv powered off unexpectedly and now only displays a white screen when i put it on charge, how do i get out of this!

scratch that now it wont even boot.

the white screen came up with options like "bootloader" and "reboot" and after navigating through the options i couldnt seem to get anything to work. after a few minutes it would even show that screen any more, and refused to even boot. but when i plug it into my laptop it recognises it as "unidentified device" or "android 1.0"      can this be fixed or is my phone dead?   

I dont have much experience with this stuff so any help would be greatly appreciated!      thanks in advance!