Download and run
Hard-SPL to unlock the phone. Instructions are available on the linked page. Turn off Anti-Virus software and Firewall during download and installation. Make sure the phone is connected to the PC via Active Sync using a USB cable and not bluetooth.
Download the EnergyROM or other ROM file and uncompress it using WinRAR or the latest beta 7-zip.
Connect the phone with a USB cable to the PC and connect via Active Sync
Run the rom update .exe file from the uncompressed ROM files. Wait until the ROM is transferred to the phone and the phone restarts and installs the ROM and boots up.