It's seem like you're still ok to use the Factory Reset (looking at the picture) though if the Factory Reset doesn't work ....
You have a couple of option since you're HTC still look non-rooted
A. Contact Telus and you might need to sent it to them (if still in warranty)
B. Just Root it remove the put it in S-Off Mode and install a Custom Rom (Personally this would be the best option)
I have a Telus/Canada DHD and I rooted him last monday and I personally think it's for the best. Some Customs ROMs are quite nice.
If you decide to root your DHD and install a custom rom you'll need to do at least 2 things, since it's a Telus ....
1. If you installed the last Update from the system updates, you'll need to downgrade it. If you have some knowledge there is a simple guide to downgrade the DHD.
*For the DHD, just follow
http://xdaforums.com/showthread.php?t=905003&highlight=downgrade+folder+download*
Take a Special note that for the Telus DHD at the line that say
-cd /data/local/tmp
./misc_version -s 1.31.405.6
You'll need to change the code for
- cd /data/local/tmp
./misc_version -s 1.31.405.3
if not, I still don't know why but the Telus one doesn't take it...
Then follow this guide : [xdaforums.com]/showthread.php?t=1259821
get ace hack kit and it should be rooted and for finish you just have to puts a custom rom
P.S for the ace hack kit : Make sure to read the EFFEN MANUEL ~_^