How can i get htc evo factory settings back on my evo because they too were deleted on an unsuccesful root?

i rooted my phone using un-revoked, then the gingerbread update came out then it would update cause of root so i went into boot mode used rom manager to delete everything before it was all backed up and even the phones operating system was deleted along with anything else that makes it come on but it works as long as you flash a whole new rom but i am needing to go back to factory setting and operating system and such. (all of the phones system, setting options and stuff that is not able to be touched before rooting) Soo... how do i get these orginal stock things back???