i had similar.the charge light wouldnt go on and the backlight didnt seem to work... i could see the splash screens but it stuck on HP screen...several hard resets and soft resets didnt work. so i put it in boot loader mode. then in the cradle and started chrismrules bootloader program... it saw the ipaq asked which rom then it slowly reloaded the rom and after a hard reset and a soft reset i had it back.reloaded the backup (sprite backup) and i only lost 2 calendar spots..
try to reflash it even if it seems dead....cant really hurt if it is dead...
HX4700 WM6.1 ROMs - xda-developers
use this link for some roms....
EDIT.....
just a thought , but is the battery door switch ok? if it isnt shut properly the ipaq wont boot.....it may be faulty.. or the bat door not seated? there is a link somewhere on these forums about cheating the door switch...