There is a new driver for the HTC Sync, you probably need to DL that before it will work.
If that doesnt work take the phone into a store and have it updated. The updated driver is at the Sprint and HTC websites.

 

idk if it will solve your problem, but i didnt have HTC Sync installed on my comp, and i just installed it from my phones SD card.

mount your phone and open up the HTC Sync folder and run the HTCSync application.

backup your contacts via your gmail account (i find this easir than using the HTC sync)

then just run the RUU file on your computer and your phone should b good to go

 

I had the same problem after installing the 2.1 update on my Hero/Sprint. I deleted an reinstalled HTC Sync 2.0.33. Same problem...phone looking for HTC Sync on my PC, but doesn't find it and quits. THIRD attempt works. Here's what I did. Went to ALL PROGRAMS, went to HTC Sync, and LEFT HTC Sync in place. Opened up HTC DRIVER, and UNINSTALLED the driver. Finally, opened up the downloaded 2.0.33 installation .exe, and it saw that HTC Sync already installed, gave me the option to REPAIR. I clicked REPAIR. When it finished, I rebooted my PC. brought up HTC Sync, and plugged in my phone with the usb. Now I got the NEW HARDWARE FOUND sequence of messages, and an HTC window came up allowing me to "name" my phone and select options. Following that, the problem went away.

I can only guess that perhaps the old driver got left in place when I installed 2.0.33 and manually deleting it fixed the problem.

All this being said, HTC Sync has other known (and continuing) problems syncing properly with OUTLOOK 2007. Always, always backup up your OUTLOOK .pst file before running Sync and you'll save yourself a lot of headache.

I don't SYNC to google.