Remote control for JVC TV stopped working

Without a remote control, you can't. If you wish to buy its original remote control, contact the authorized service centre, or authorized dealer to your device brand. They can either give you a genuine remote control to your device, or can direct you, from where can you purchase a suitable one.
To select a proper universal remote control, you should know about the number of digits to its set-up codes. There are 3 digit, 4 digit, 5 digit, 2 digit and even single digit codes, to some brand devices. After confirming this, check the sites linked here. Both the sites have set-up code list and set-up procedure to many popular brand remote controls. Check which brand remote control has set-up code/s to your device brand, and buy that one according to availability. Brand name of the remote control isn't a matter, but it should have set-up codes in its code list, to the device brand you have.
Please note: Every new universal remote control will have set-up code list, and set-up procedure along with its pack. Never accept a remote control, that hasn't both of this. For more details about the set-up codes, visit the sites.
http://electrohelponline.blogspot.com/
http://remotesearch.blogspot.com/
Universal remote controls are available at most of the electronic spare part selling shops. Visit some on-line sites too, which deals with electronic spare parts.

Hola me gustaria saber si me pueden ayudar tengo un tv jvc que al encenderlo solo me cambia todos los colores en la pantalla

sounds like the remote batteries could be bad or the buttons on the remote need to be cleaned. some JVC TV remotes, I'm not familiar with this particular one though, can be cleaned using a clean pencil eraser. Be careful opening the remote because some parts can fall out or you can damage the connections to the LED emitter that sends the signal to the TV. Also the solder connections on that LED could be bad.

If you point a mobile phone camera toward the output of the remote, you will see if it works or not.
Hope that helps.

What remote? It depends on the remote. Different remotes use different codes. They all have a code search function that you can use to find the code.

Try this

1. Get camera phone
2. set camera phone to to take picture
3. point remote at camera and look at the camera display
4. press buttons on the remote, you should a light from the Remotes IR.
5a. If NO light is seen, your remote is broken. you can try replacing the batteries to double check
5b. if Yes, light is seen. Your remote is working and you may have a problem with the TV.

As a double check, get a remote you know is working and try the same thing to verify that you are checking the remotes correctly.

The IR sensor in the tv is probably weak, you could make a mountain out of a mole hill and get it replaced (using your friends receipt ^_^) but there's nothing to be done about the sensor.