Totally unresponsive to key imputs; display shows ERR

This could be a lot of things. IT could be a switch connection or a chip that has failed, could be a solder connection that is bad. Without proper equipment to send a signal into the unit and trace it, you may not be able to find the problem.

You buy service repair info. (manual) an do the diagnostic procedures for those code's . Which include testing the electrical circuit's . or view video's on youtube showing how to diagnose .

YOU HAVEN"T DIAGNOSED ANYTHING YET ! YOU READ CODES ,THAT'S ALL
I have diagnosed my 2001 Nissan xtrail with 2 errors: P0102 mass or volume air flow circuit low imput & P0113 intake air Your best bet , take it to a qualified repair shop.

Need to know the make and model.

Is the aux imput for tape or cd only? Or is it a dedicated phono imput?
If it is for tape or CD only it won't work has the cartridge from the deck needs a magnetic pre-amp.
If the amp doesn't have a phono imput you can get a pre-amp for cartridges from your local electrical shop. This will plug into your deck and then into the socket of the amp.
If the aux on your amp is a phono socket, assuming the record deck is working, then the pre-amp (inside your amp) for the cartridge has failed. It generally is located near the imput socket, chances are it will be single IC. It's a fair bet the IC will have failed, they tend to be static sensitive types prone to fail at the drop of a hat!

Make sure that it is pluged in to Video imput and not different imput it should be yellow not red,blue,or,green unless this is the way you connect it to your T.V. If it is make sure these cables are connected properly.

Perhaps this device at creative.com (The link provided for you) or something similiar will do the trick for you.
http://us.creative.com/products/product.asp?category=209&subcategory=668&product=16186&nav=1

It connects to a USB port. You have 2 on the right side of your laptop. The device has two RCA ports which should provide the connections you seek.

A device like this one or similiar should give you the best "Quality" audio transfer.

But if cost is more of an issue, you can find "Patch cables" at you local electronics store to go from RCA jacks to stereo headphone jack this will allow you to port the information in through your Microphone jack.

Hopefully this helped you,
Dave

If you remove the batteries and reinstall, does the display indicate Hold at some point? The hold button sometimes breakes and doesn't activate the switch. Pop off the hold button and move the internal switch manually.

YOU MUST GO INTO YOUR COMPUTER CONTROL PANEL TO SET THE DISPLAY SETTINGS FOR YOUR LCD.

This is a common issue with HDMI. Try unplugging the TV for 2 monutes and also reset the cable box as well by inplugging.

if you scan down below channel 2 doesn't video show up? otherwise there should be a input / video button