hi i've made a backup of the whole disk, then formatted it and reinstalled windows 8.1 (uefi mode) again.
Then immediately installed hp software, and it works!
so it's something related with windows.
copied macromed folder from both system32 and syswow64 in an usb pen, then restored my backup.
Obviously hp solution center doesn't work again.
Copied the macromed folder just saved from the new fresh system in my old system.
registered both flash.ocx by regsvr32, but no way. the error remains!
i don't know what is going on, but i don't want to format it again.
I've just done it some days ago, and lost about 2 days to reinstall all my softwares.