I think we need to go manual. The point of step1 was for the program to push the DIAG apk to the phone (we can do that manually). And the point of the step2 was to start a program called zadig(manually also). HOWEVER we need the step3 button to root our phone and it doesn't unlock unless you press buttons 1 and 2. And YES you're phone will be in DIAG mode whether you boot it or not.
I have an idea. We need to manually do steps 1 and 2. But BEFORE ANY OF THAT we need to do "Step0". I'll show you.
Prerequisites: Uninstall ALL the drivers from control panel(IMPORTANT! ANYTHING WITH "LG DRIVER") and install one driver I linked above. Connect the phone to the computer to install the rest of the drivers. Reboot.
Step0) Open up One Click Root and (with your phone DISCONNECTED) press step one. This will unlock step2. Now press Step2 and that'll unlock Step3. Now minimize the program, we will use it later. DO NOT CLOSE IT.
zach you may skip step1 since you're phone is already in DIAG mode. But you may do it just to make sure it's STILL in DIAG mode, just in case.
Step1) there should be a file in your platform-tools called "LG_OE_DiagMode-debug-unaligned" COPY this to your sdcard via a computer and put the sdcard but in your phone. Navigate on your phone to where you put that file and install that apk file. Now open it and press "Push Me" Now Enable Diag Mode.
Step2) Now open a .exe program in platform-tools called zadig this will install your needed drivers. REMEMBER, you ONLY need install:
CDC Serial(Interface 0)
LG Android USB Device(Interface 2)
LG Android USB Device(Interface 3)
Install/replace the drivers.
Step3) Now comes the sketchy part. Connect your phone to the computer and click step3 from One Click Root. If successful, you're phone will boot 2/3 times and One Click Root will exited automatically. Good luck.