make sure you are in fastboot when launching your recovery(select fastboot from the hboot menu)
make sure you are entering "fastboot devices
" to try and get a response from the phone. if you can get to fastboot,you should be able to install drivers and launch your recovery.
i personally recomend these htc drivers
from revolutionary,if thats not what you used
make sure that you do NOT have htc sync,pdanet,easy tether,or any other program capable of comunicating with the phone running on the PC,it will cause issue.
try different usb cables and ports
you can try updating the drivers manually:
plug in the phone in fastboot,find it with device manager. right click,then update drivers,then point the wizard to the extracted driver file.
if you can get your driver issue figured out,and your phone seen in fstboot, you might consider running the ruu for the latest,global firmware to update things,if restoring a backup does not work.
directions to upgrade to the global update here: Scottys noob friendly root guide-start to finish
hope that helps
on,one last bit... i cannot take credit for scrosslers cleanroms. i am scotty85,he is scott scrossler