Sounds like you have the Jensen RV212T... Many have had issues with the 'blank screen' - leaving only the volume and CD playing functions working.
Here is the full thread:
http://www.thorforums.com/forums/f10...creen-775.html
I had some success with removing and completely unplugging the radio - and then replacing.. but that is just a workaround...
As Jamie posted while i was typing - if you are still under warranty - call Jensen and see if they will send you a replacement (hopefully the 215).
I finally got mine replaced under a service plan - but they got another 212...
(I was out of warranty when mine failed the first time.)