If you flashed the generic rom from the link you mentioned then your phone should not be rooted anymore. to verify, you can utilize the adb command from the SDK to open a shell on the phone, and then type 'su'. If your phone is not rooted, you should recieve the following response:
su: permission denied
If the prompt changes from a '$' to a '#' then you are still rooted. By flashing to the original rom then HTC should have no way of knowing that the phone was rooted before, unless you tell them.
Thank you so much. I get permission denied so it must not be rooted anymore. But what about the fact that i can get into "Cyanogen’s Hero Recovery Image", would this invalidate my warrenty? How do i remove it?