You're using a Sprint phone, right? If so, download and install this:
Goo.im Downloads - Downloading RUU_Shooter_S_Sprint_WWE_2.17.651.5_Radio_1.06.00.1216_NV_NV_spcs_1.42_release_233304_signed.exe
The way you do it is you connect your phone to your computer, then go into Settings > Applications > Development > and check USB Debugging.
Install the drivers for the phone (if you haven't already). If you don't have the drivers, install HTC Sync.
Then run that program. It takes a few minutes to boot. It'll force the upgrade to the latest OTA (2.17.651.5).
It's normally a rooter's tool to return to 100% stock, but it'll work stock phones to upgrade, too. It does not root your phone. It's just like taking the OTA, but you're installing through a PC instead of over the air.