I'm sure that it has nothing to do with display settings for it is giving display for other file types like wmv, mpeg.

Look for/perform the following;

(If you've already done the first section (1 : 4), skip to step 5)

1.
In Category View of Control Panel, click Add or Remove Programs.

2.
Click Remove a program, and then, at the top of the list, select the Show updates check box.

3.
In the Windows Updates section, click Windows Media Player 11, and then click Change/Remove.

4.
If prompted, restart your computer, and then log on as an administrator or a member of the Administrators group.


5.
In Control Panel, click Add or Remove Programs.

6.
In the Windows Updates section, click Windows Media Format 11 Runtime, and then click Change/Remove.

7.
If prompted, restart your computer, and then log on as an administrator or a member of the Administrators group.

8.
In Control Panel, click Add or Remove Programs, and then click Remove a program.

9.
Click Microsoft User-Mode Driver Frameworks Feature Pack 1.0, and then click Change/Remove.


Note

If you remove Windows Media Player 11 and the Windows Media Format 11 Runtime, and you try to play a protected file, you may get an error message indicating that the Player cannot play, burn, or sync protected files. To resolve the problem, you can install the Windows Media Format 9.5 Runtime. For information about installing the Runtime, in the Microsoft Knowledge Base, see article 891122, "Update for Windows Media Digital Rights Management-enabled players."
http://support.microsoft.com/?kbid=891122

You can also use System Restore to roll back to the previous version of the Player. For more information about System Restore, see Use System Restore to Undo Changes if Problems Occur.
http://www.microsoft.com/windowsxp/u...emrestore.mspx


Post back with the results.

Try a System Restore.

Start\All Programs\Accessories\System Tools\System Restore

Choose a restore point which preceeds the problem.

Try using VLC player to play the files it has all the codecs you need to play mostly any movie files. It should work http://www.videolan.org/vlc/

yeah i know that & thats what i have been doing.
I'm used to having them played in wmp & some playlists are there already. So, just trying if there is someway to retrieve the wmp to the old condition + to know why that occurred. Anyway thanks for the reply.

Have tried to all possible restore points which i felt were safe but the system replies back with some problem in the restoring process.

yeah this one worked with the 1st 4 steps itself. got back to wmp10.
but still the "video not visible" problem not solved