What is the signal source? How do you have the TV connected to the source?
For most video equipment (dvd players and other set top boxes), connect the TV to the device with everything turned off. Turn on the TV then switch to the appropriate input. Finally turn on the source device.
Check the cables to make sure that they are fully seated. Try using different cables (to rule out damaged cables).
If your source is OTA antenna, check that the antenna hasn't been rotated. (This assumes it has worked in the past.) Check your wiring for any damage. If you have an amplifier or switch in use, remove it and check if the signal comes through. (You can use a coax coupler to connect the two wires directly). If the signal is fine, replace the amplifier. If you were using a switch, either replace it with a direct replacement or with an amplified switch (in case the signal was reduced beyond the level that the tuner can receive). Also check if the fuse has been damaged, if you have a surge protection/grounding system on the antenna system. Replace the fuse if needed (this can also be the issue for satellite and some cable installs).
If your source is a computer, try a different video cable. Turn off everything before connecting the TV to the computer and turn on the TV first when ready to restart. Make sure that the video port that you are using is active. (Desktops often have on-board video and separate video cards. Only one set of ports is live.) Depending on the computer, you may need access the BIOS with the computer connected to a different monitor to change the active port. (Press Esc, F1, F2 or F10 depending on the machine immediately after turning on the computer. Sometimes I miss the timing and have to shut down the computer a second time and repeatedly hit the key to access the BIOS.) Make sure that the computer is sending a resolution of 1360x768 at 60 Hz.
If you are connecting a computer to the TV with an HDMI cable, try using the VGA (RGB) port instead. The computer's signal is not the same as that of other video set top boxes. This TV does not support a computer on HDMI.
For a laptop, you also may need to enable the external video port. Then set the OS to use the external port. (On my HP laptop with Windows 7, I can do this by right-clicking on the Display and choosing Graphics Properties. Then I can set the monitors to Dual, Extended (mode) and Laptop monitor or External Monitor (display). Then click Apply followed by OK (in a second window) to accept the changes. For other laptops, you probably have a shortcut or can do it in the OS.
If the problem occurs on all sources, the input board may be damaged on the TV. (A power surge (lightning strike) could cause the damage.) If the TV is under warranty, you should contact Vizio.
Since the inputs are directly soldered to the main board on this TV, unless you are skilled at soldering, you would need to replace the entire board. Disassemble the TV and check the current board before replacing. There are several main boards available for the TV. Shopjimmy.com lists the VA220E parts as out of stock. Partstore.com has some of the boards in limited numbers: http://www.partstore.com/Model/Vizio/Vizio/VA220E.aspx
I hope this helps.