Help with unroot

[Thermaltake868]

Hi I have unroot my phone wiht revolutionary and install alpharev hboot, now on my desire is sebastiaan runnymede, and I want to unroot my phone to have stock hboot and froyo or gingerbread but I think froyo would be better cause gingerbread was pretty f... So can someone help my how to do it I downloaded that RUU_Bravo_Froyo_HTC_WWE_2.29.405.5_Radio_32.49.00.32U_5.11.05.27_release_159811_signed but when I try to update he said faild and some error.

EDIT:
I found droidzone method, testing it right now.

 

[Thermaltake868]

I can't enter recovery, when I do I only see some mobile with red exclamation mark, and I don't have any OS on him currently, please someone help me need to fix this asap.

Can I install somehow recovery separately ?

EDIT:
I manage to install RUU I run fastboot I downgraded hboot from alpharev site, and install it successfully.