Not playing dvds previously played

Check an other known disc. If it play well, the the disc you're trying to play is region protected. Electro help

You need to go in the menu and change the region code. yours is not set for amarican made dvd's

If you are in region 1 for DVD's you can't play any other region. You have to buy the right region DVD for the player. http://en.wikipedia.org/wiki/DVD_region_code

Commercial DVDs are released with region codes that restricts in which part of the world they can be played. Consumer DVD players sold in those regions are pre-configured with the correct region code for the given sales area. The United States, Canada, Bermuda, and U.S. territories are region 1. Europe (except Russia, Ukraine, and Belarus), The Middle East, Egypt, Japan, South Africa, Swaziland, Lesotho, Greenland and region 2.

sources:
http://forums.techguy.org/miscellaneous-tech/972005-dvd-wont-play.html

To change the Region code on your player, open Control Panel - System - Hardware - Device manager, and click on DVD/CD ROM drives, then right click on the DVD drive and click Properties then click on DVD Region.
You can enter a new region and it also shows you how many changes have been made.
NOTE you can make only 4 changes and the player will lock permanently on the 4th change.
If you want to play DVD from any region you maybe able to upgrade the firmware to make it region free BUT if you make a mistake or installed the wrong firmware the player will be a piece of junk.
The best solution to make the player region free is to install a piece of software that allows you to play DVDs from any region. There are several available on the Internet but my favourite is DVD-Region Free
From: -
www.dvdidle.com/dvd-region-free.htm

no solution but i have exactly the same problem - the system has suddenly stopped playing any dvds at all including ones it has previously played - i get no sound or picture just a circle with a + sign in the middle on the dvd digital display

did you find any solutions elsewhere?

yes the sony dvd players is made for certain regions it wont play other discs that are not either region one or two new zealand i think is region 3

Or region code conflict or you are burning your own DVD's wrong way on wrong type or unit broke

Hi do you have the model number? If you check videohelp.com you can find Multi Region unlocking codes.

It sounds like the DVD region (a setting in both your OS and your DVD hardware) may have been changed. DVD regions are the agreed upon method (by entertainment companies, hardware manufacturers and governments) to limit cross-border sharing of media. Most valid (read: non-pirated) DVDs have a region code. Your DVD drive will only play DVDs with a region code that matches the DVD region code set on the DVD drive.

You didn't mention your OS but if you are running Windows XP then go to Start->Control Panel->System->System->Hardward->Device Manager and find your DVD player. Right-click the DVD player and select Properties from the menu and you should see a properties dialog-box with a DVD region tab. This is where you can change the DVD region that your player will recognize. Be careful, don't play around here, most DVD players have an embedded limit on the number of times (4-or-so) the DVD region can be changed.

Hope this helps.

-Ed