Okay, so, that means that you flashed a recovery that isn't compatible with your phone's screen.
Install the Android SDK:
http://dl.google.com/android/installer_r18-windows.exe
Install the Java JDK:
Java SE Development Kit 7u3 Downloads -- choose the version that corresponds with your computer, i586 for 32-bit and x64 for 64-bit.
After all that, go to Start > Programs > Android SDK Tools > SDK Manager and UNCHECK any boxes that are checked already.
Then, check the box next to Android SDK Platform Tools
Press the button that says 'Install 1 package...' on the bottom right. Let it do it's thing. Go have a smoke or something in the meantime.
Now, here's where the fun begins. Download the following two files and copy them to your SD card.
http://dl.dropbox.com/u/72059024/flash_image
http://dl.dropbox.com/u/72059024/VM670NH_recovery.img
Put the card back in your phone. Pull battery, put back in, hold vol down, home, and power, and let go as soon as the LG logo appears. Plug your phone into your PC.
Go to "Start" > Run and type in "cmd" (without the quotes.) Press enter.
cd into the platform-tools folder that the Android SDK installed. If you left everything default, your command will look like "cd C:\Program Files\Android\android-sdk\platform-tools\"
type in "adb devices" and press enter. You should see a string of numbers and then the word 'recovery'.
Now, type "adb shell" and press enter.
Then, in the adb shell, type the following commands, one at a time.
su
mount -o remount,rw /system /system
cat /sdcard/flash_image > /system/bin/flash_image
chmod 755 /system/bin/flash_image
mount -o remount,ro /system /system
flash_image recovery /sdcard/VM670NH_recovery.img
If you get any errors, STOP, post back here, be as detailed as possible.
If you get no errors, and it's done doing it's thing, unplug your phone. Pull the battery, put it back in, and boot holding vol down, home, and power, and let go of power at the LG logo. You should now be at your custom recovery, which you can use to flash the LG Stock update.zip, and then go from there.